Showing papers in "Journal of Pest Science in 2010"
TL;DR: A review of information on the invasion by T. absoluta, its ecology, and potential management strategies, including data that may help the implementation of efficient biological control programs, indicates an urgent need for efficient and sustainable management methods.
Abstract: The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato originating from South America. After its initial detection in eastern Spain in 2006, it rapidly invaded various other European countries and spread throughout the Mediterranean basin. If no control measures are taken, then the pest can cause up to 80–100% yield losses in tomato crops in recently invaded areas and may pose a threat to both greenhouse and open-field tomato production. The exceptional speed and extent of T. absoluta invasion have called for studies documenting its biology and ecology, while indicating an urgent need for efficient and sustainable management methods. The development of approaches to manage T. absoluta would be facilitated through a detailed revision of information on this pest in its area of origin. This review combines information on the invasion by T. absoluta, its ecology, and potential management strategies, including data that may help the implementation of efficient biological control programs. These programs, together with a variety of other management tactics, may allow efficient integrated pest management of T. absoluta in Europe and Mediterranean Basin countries.
804 citations
TL;DR: Results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.
Abstract: Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT50) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT50 values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC50 values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.
101 citations
TL;DR: Results suggest that D. stramonium extracts could be used to manage the two-spotted spider mite.
Abstract: The ethanol extracts obtained from both leaf and seed in the Thorn apple (Datura stramonium L.) (Solanaceae) were investigated for acaricidal, repellent and oviposition deterrent properties against adult two-spotted spider mites (Tetranychus urticae Koch) (Acari: Tetranychidae) under laboratory conditions. Leaf and seed extracts, which were applied in 167,250 and 145,750 mg/l concentrations, respectively (using a Petri leaf disc-spray tower method), caused 98 and 25% mortality among spider mite adults after 48 h. The simple logistic regression analysis showed that the independent variable, an increase in the dose of leaf extract was associated with a significant increase in the death rate of T. urticae females, but an increase in the dosage of seed extracts did not have a significant effect. Using probit analysis and estimating the parameters with a confidence limit of 95%, we determined the LC50 values of leaf extract to be 70,593 mg/l. According to Pearson’s χ2 test, mites showed the strongest run off to bean leaf surfaces sprayed with both leaf and seed extracts (in sub-lethal doses: <7,500 mg/l and <25,000 mg/l, respectively) and moved towards surfaces that had not been sprayed with extracts. Furthermore, repeated measures ANOVA indicated a significant difference between the number of eggs laid on unsprayed bean leaves compared to bean leaves that were sprayed with leaf and seed extracts at sub-lethal doses, 2,500 and 25,000 mg/l concentrations, respectively. These results suggest that D. stramonium extracts could be used to manage the two-spotted spider mite.
98 citations
TL;DR: Cauliflower was the most nutritive and preferred host plant for Spodoptera exigua and could be useful to design cultural management strategies, which may include trap cropping.
Abstract: Host plants play an important role in population increases and outbreaks of cosmopolitan polyphagous insect pest, such as Spodoptera exigua (Hubner; Lepidoptera: Noctuidae). We investigated the impact of various host plants (cauliflower, peas, and wheat) on fitness and relative growth rate of S. exigua and intrinsic rate of population increase. The S. exigua population was collected from cauliflower fields from Multan, Pakistan. Comparison of various life-history traits on three different host plants revealed significant differences that might be correlated with the fitness costs. The mean number of eggs laid by female reared on cauliflower was significantly greater than on peas or wheat. Similarly, eggs viability, intrinsic rate of population increase, adult eclosion, and adult’s longevity were significantly higher on cauliflower than on peas and wheat. The low survival on peas and wheat suggest the unsuitability of these host plants, while the higher pupal weight on cauliflower suggest that it provides better food quality to S. exigua compared with peas and wheat. On peas and wheat, fitness declined with each generation suggesting that the average fitness of individuals may decline due to the elimination of insects with higher fitness. Our results suggest that cauliflower was the most nutritive and preferred host plant. Such results could be useful to design cultural management strategies, which may include trap cropping.
83 citations
TL;DR: This work studied how temperature affects important parasitoid efficiency-related biological traits under laboratory conditions of two strains of T. cacoeciae and found that the French strain showed highest fecundity at 25°C with wasps that had been reared at 20 or 20°C, but only when wasps were previously rearedat 25 or 30°C.
Abstract: Parasitoids’ efficiency in controlling pests depends not only on their ability to parasitize their hosts but also on how much they are adapted to climatic conditions (notably temperature) of the area where they are planned to be released. In addition, the optimal conditions for production of parasitoids used for inundative releases like Trichogramma spp. may also vary largely as a function of strains. Using the parasitoid Trichogramma cacoeciae Marchal as biological model, we studied how temperature affects important parasitoid efficiency-related biological traits under laboratory conditions. Emergence, mortality rates and fecundity of two strains of T. cacoeciae, one originating from France (Alsace) and the other one from Tunisia (Degache), were compared at constant temperatures of 15, 20, 25 and 30°C. The parasitoids of the French strain showed highest fecundity at 25°C with wasps that had been reared at 20 or 25°C. The Tunisian strain showed the highest fecundity at 25°C, but only when wasps were previously reared at 25 or 30°C. For both strains, the highest mortality occurred among wasps that had laid eggs at 30°C. Emergence rates were relatively high at all temperatures, although the French strain did better at 15–25°C and the Tunisian one at 20–30°C. Because of the differences in biological traits of these two T.cacoeciae strains in relation to the temperature, a judicious choice must be made among the various strains when using this species in biological control programs.
76 citations
TL;DR: The principal response curve (PRC) analysis revealed a significant deleterious effect of Surround WP on the natural enemy arthropod community of the olive grove.
Abstract: The particle film technology based on processed kaolin sprays has been recently introduced for the control of the olive fruit fly Bactrocera oleae (Rossi), the key pest of olive groves. A 3-year field experiment was conducted from 2005 to 2007 at Villarejo de Salvanes, Spain to assess the efficacy of a kaolin-based product (Surround WP) for controlling B.oleae and two other olive insect pests: the olive black scale Saissetiaoleae (Olivier) and the olive psyllid Euphylluraolivina (Costa). The effects of Surround WP on the arthropod community of olive trees and on natural enemies were also evaluated. In a high olive fruit fly pressure year (2007), Surround WP sprays significantly reduced the incidence of B. oleae and that of S. oleae. However, Surround WP treatments did not have any effect on E. olivina populations. Both the abundance and the diversity of arthropods were reduced by Surround WP treatment. The principal response curve (PRC) analysis revealed a significant deleterious effect of Surround WP on the natural enemy arthropod community of the olive grove. The most affected taxa were the following: the coccinellids Scymnus mediterraneus Iablokoff-Khnzorian, Stethorus punctillum Weise and Hyperaspis reppensis (Hbst.); the mirid Brachynotocoris ferreri n. sp. Baena (in litteris); different species of Orius and the families of Philodromidae, Scelionidae, Pteromalidae, Chrysopidae and Aphelinidae. Processed kaolin is proposed as an alternative to chemical control of the olive fruit fly. However, the effect of processed kaolin treatments on natural enemies should be taken into account in a rational pest control programme.
74 citations
TL;DR: IT835-720-20 is a promising variety with useful genetic resource for cowpea breeding programs aimed at developing resistant varieties against A. craccivora, and may suggest that antibiosis is the modality of resistance.
Abstract: The cowpea aphid, Aphis craccivora Koch, is an important pest of cowpea Vigna unguiculata (L. Walp.) in most tropical regions where cowpea is grown. We used life table and population parameters of the cowpea aphids reared on five cowpea varieties to assess the degree of host plant resistance. The five varieties were Blackeye, B005-C, INIA-37, IT835-720-20 and TVX3671-14C-OID. The parameters measured were fecundity, survival, intrinsic rate of natural increase, pre-reproductive period and relative growth rate of cowpea aphids. Our hypothesis was that cowpea varieties resistant to A. craccivora would have significant effects on life table parameters of the aphid when compared to a susceptible variety. Mean fecundity, age-specific fecundity, survival rates, intrinsic rate of natural increase (r
m), pre-reproductive period and relative growth rate differed significantly among varieties. Fecundity, survival, intrinsic rate of natural increase and mean relative growth rate were significantly lower on variety IT835-720-20 compared to susceptible variety Blackeye. The pre-reproductive period was significantly delayed on variety IT835-720-20 compared to other varieties. The adverse effects of variety IT835-720-20 on life table parameters of A. craccivora indicate the presence of host plant resistance. Prolonged pre-reproductive period and reduction in reproductive performance of A. craccivora on variety IT835-720-20 may suggest that antibiosis is the modality of resistance. However, further detailed studies that include determination of biochemical and morphological characteristics that mediate resistance need to be carried out. IT835-720-20 is, therefore, a promising variety with useful genetic resource for cowpea breeding programs aimed at developing resistant varieties against A. craccivora.
74 citations
TL;DR: Production and biocontrol efficacy of culture filtrates containing cuticle degrading enzymes from three isolates of Isaria fumosorosea against diamondback moth (Plutella xylostella) was observed and can help in the development of enzyme-based biopesticides against P. xylstella.
Abstract: Production and biocontrol efficacy of culture filtrates containing cuticle degrading enzymes from three isolates of Isaria fumosorosea against diamondback moth (Plutella xylostella) was observed during this study. This fungus when cultured in liquid medium having different carbon sources showed maximum biomass production when 1% chitin was added as carbon source. These isolates when grown in liquid culture conditions having 1% chitin as source produced cuticular degrading enzymes (proteases (Pr1 and Pr2), chitinases, chitosanase, and lipase) in a sequential manner and the production of these enzymes differed from control. Biocontrol assays with P. xylostella showed that the culture filtrates of I. fumosorosea were potent antifeedants because reduction in the feeding rate and body weight of the larvae was observed. Similarly, reduction in rates of successful pupation, adult emergence was observed when the culture filtrates were applied topically. At the end of the test period, the lowest ST50 value (1.57 ± 0.20 days) was recorded for insect groups treated with culture filtrates from isolate IF28.2 when compared to the control. In view of the need for safer and environmentally friendly pest management tools, the present study can help in the development of enzyme-based biopesticides against P. xylostella.
71 citations
TL;DR: It is indicated that the natural product DE has great potential to replace synthetic pesticides commonly used in stored product pest management and can be improved by adding certain monoterpenoids against certain insect pests.
Abstract: We investigated the effects of two commercial diatomaceous earth based insecticides (DE), Protect-It® and SilicoSec®, the nano-structured silica product AL06, developed by the section for Urban Plant Ecophysiology at Humboldt University Berlin, and the monoterpenoids, eugenol, and cinnamaldehyde on two stored product pests, Callosobruchus maculatus and Sitophilus oryzae. Protect-It® was more effective than SilicoSec® against C. maculatus while the reverse was true for S. oryzae. Generally C. maculatus was more sensitive towards DE and silica treatment than S. oryzae. Mortality rate of both pest species increased when DE’s were applied to food commodities previously treated with a monoterpenoid. In admixture experiments, the toxicity of SilicoSec® + cinnamaldehyde (LD50 = 42.73 ppm), SilicoSec® + eugenol (LD50 = 24.30 ppm), and Protect-It® + eugenol (LD50 = 2.60 ppm) was increased over DE alone against S. oryzae. Both substances showed a synergistic effect considering their co-toxicity coefficient relative to the LD50-value. In contrast, we could not find any synergistic effects in experiments with C. maculatus. Here only Protect-It® + cinnamaldehyde (LD50 = 20.84 ppm) showed an additive effect while all other combinations of monoterpenoid and DE indicated antagonistic effects. In addition to contact insecticidal effects both monoterpenoids showed a strong fumigant action. The presented results indicate that the natural product DE has great potential to replace synthetic pesticides commonly used in stored product pest management. Efficacy of DE can be improved by adding certain monoterpenoids against certain insect pests.
67 citations
TL;DR: The study points out the importance of including the host plant of P. xylostella when conducting studies aiming to select the most efficient parasitoid against this pest, and examines the potential of various species (and various strains of some species) of Trichogrammatidae to control this pest on cauliflower in greenhouse in France.
Abstract: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of cultivated Brassica worldwide, including those grown in greenhouses like cauliflower. In this article, we evaluate the potential of various species (and various strains of some species) of Trichogrammatidae (Hymenoptera: Chalcidoidea) to control this pest on cauliflower in greenhouse in France. We assessed the parasitism levels on P. xylostella of 17 Trichogrammatidae strains, belonging to 12 different species (2 indigenous strains from France), under greenhouse conditions. Parasitism levels for each of the Trichogrammatidae species and strains were determined on cauliflower leaves (Brassica oleraceabotrytis L., Brassicaceae) infested with P. xylostella eggs. Nine strains parasitized 60% (or more) of the P. xylostella eggs. Compared to previous results in laboratory conditions, climatic conditions of the greenhouse did not influence parasitism levels. The presence of the cauliflower plants may have a positive effect on eight strains, a negative effect on four strains and no effect on five strains. Our study points out the importance of including the host plant of P. xylostella when conducting studies aiming to select the most efficient parasitoid against this pest.
67 citations
TL;DR: No correlation was detected between the toxicity of the mentioned compounds to larvae and the known capacity of the acetogenins 1, 2, and 4 to inhibit the NADH oxidase, indicating that the inhibition of the mitochondrial complex I is not the only cause for larval mortality of S. frugiperda.
Abstract: Several species of the large family of tropical plants Annonaceae have been intensely investigated over the last 20 years, mainly because of the discovery of annonaceous acetogenins. These compounds are powerful cytotoxics, with potential applications as insecticides, antiparasitics, acaricides, fungicides, and antitumor drugs. Annona montana Macfad. (Annonaceae) grows in Santa Cruz de la Sierra, Bolivia, where an infusion of leaves is used for the treatment of lice, influenza, and insomnia. The major acetogenins from a Bolivian collection of A. montana, annonacin (1), cis-annonacin-10-one (2), densicomacin-1 (3), gigantetronenin (4), murihexocin-B (5), and tucupentol (6), were evaluated for their antifeedant and toxic effects on Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), a serious pest affecting corn crops in Argentina. All the acetogenins produced 100% mortality during the larval or pupal stages at 100 μg of treatment per gram of diet. In addition, compounds 2, 3, and 4 deterred more than 80% feeding at the same dose. Relative toxicity values of LD50 for the strongest larvicidal compounds 1, 2, and 4 were determined, indicating that the three compounds are effective natural insecticides. This is the first report on the antifeedant and toxic effects produced by the particular type of acetogenins, the mono-THF acetogenins, on the lepidopteran S. frugiperda. No correlation was detected between the toxicity of the mentioned compounds to larvae and the known capacity of the acetogenins 1, 2, and 4 to inhibit the NADH oxidase, indicating that the inhibition of the mitochondrial complex I is not the only cause for larval mortality of S. frugiperda.
TL;DR: The insecticides exhibiting no, very low or low resistance, and no cross-resistance among themselves can be exploited in devising an insecticide resistance management strategy to combat whitefly resistance in the field.
Abstract: Field populations of adult whiteflies, Bemisia tabaci, from Pakistan were monitored from 1992 to 2007 for their susceptibility to seven organophosphate and three carbamate insecticides using a leaf-dip method. Malathion, quinalphos and chlorpyrifos generally exhibited no or a very low level of resistance in B. tabaci over a 16-year monitoring period. Resistance to profenofos, triazophos, parathion-methyl and ethion was usually low to high up to 1995, and then it dropped to very low levels during 1996–2004. Resistance levels again picked up from low to moderate levels for triazophos during 2005–2007, for parathion-methyl during 2003–2007, and for ethion in 2006. Among carbamates, thiodicarb resistance was high during 1994–1996, which dropped to moderate levels in 1997 and 1998 and to very low levels during 1999–2001, but again increased from low to high levels during 2002–2007. Methomyl resistance was moderate in 1994 and 1995, which dropped to very low levels during 1996–2002, and then increased to low levels during 2003–2007. Butocarboxim resistance remained very low during 1994–2003 and then increased from low to high levels during 2004–2007. The insecticides exhibiting no, very low or low resistance, and no cross-resistance among themselves can be exploited in devising an insecticide resistance management strategy to combat whitefly resistance in the field.
TL;DR: Carbosulfan and flubendiamide may be used for the control of L. orbonalis in eggplant and the performance of azadirachtin against the pest both in the laboratory and field trials was the poorest while that of carbosulfAn and flubsulfan was the best.
Abstract: Shoot and fruit borer, Leucinodes orbonalis Guenee, is a serious pest of eggplant (Solanum melongena L.). Management practices of this obnoxious pest are limited to frequent spray of chemical insecticides. Due to increasing levels of resistance of L. orbonalis to different insecticides there is an urgent need to test new chemicals. In this study, nine insecticides such as azadirachtin 0.03EC, abamectin 1.8EC, flubendiamide 24WG, chlorpyriphos 20EC, cartap 50SP, carbosulfan 20EC, thiodicarb 75WP, cypermethrin 10EC, and lambdacyhalothrin 2.5EC belonging to different chemical groups were tested against eggplant shoot and fruit borer in laboratory and field. In laboratory trial, carbosulfan and flubendiamide showed the highest toxicity against fourth instar larvae of L. orbonalis after 24 and 48 h of exposure, respectively. In field trials, they reduced more than 80% shoot and fruit infestation in winter, and 80% shoot and 70% fruit infestation in summer over control. Carbosulfan protected the highest amount of healthy fruit yield in both cropping seasons. Flubendiamide also showed the similar efficacy. Cartap and thiodicarb were moderately effective in both the seasons. Efficacy of cypermethrin and abamectin was moderate in winter but low in summer. Lambdacyhalothrin and chlorpyriphos although reduced shoot and fruit infestation of eggplant and protected higher yield as compared to control, their effectiveness was not satisfactory. The performance of azadirachtin against the pest both in the laboratory and field trials was the poorest while that of carbosulfan and flubendiamide was the best. Thus, it is suggested that carbosulfan and flubendiamide may be used for the control of L. orbonalis in eggplant.
TL;DR: Analysis of data on the premises infestation by commensal rodents collected during the 2006 Urban Rodent Survey, in Sao Paulo city, Brazil, showed that access by the building structure favours roof rat and access to the sewage system favours Norway rat, and that a natural partition of the environmental resources among the species was observed.
Abstract: This article provides analyses of data on the premises infestation by commensal rodents collected during the 2006 Urban Rodent Survey, in Sao Paulo city, Brazil. A two-stage cluster sample survey was used to visit 23,512 premises, and logistic regression models were estimated in order to understand the relationships among the risk factors and the infestation probability. The premises infestation rates were 23.1% for all rodents, 12.7% for roof rat, 9.4% for Norway rat and 1.7% for house mouse. Factors found to be related to infestation levels were: socioeconomic conditions (human development index and income), premises features (commercial, strictly residential and vacant lots), and environmental resources (access, harborage and food). The analysis of odds ratios showed that access by the building structure favours roof rat and access by the sewage system favours Norway rat. Harborage in ceiling cracks are determinant for roof rat, harborage in wall cracks and in dense bush for Norway rat, and harborage in waste or in building material for house mouse infestations. Available animal food favour all the three species, fruit trees favour Norway and roof rats, human food is important for house mouse: therefore a natural partition of the environmental resources among the species was observed. The results obtained in this article add some knowledge on the biology and behaviour of commensal rodents.
TL;DR: The high level of resistance in variety Sandy can serve as base for genetic improvement of C. pepo focusing on the development of resistant varieties to B. tabaci B biotype, in eight Cucurbita pepo varieties.
Abstract: The objective of this study was to investigate the potential resistance mechanisms to Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B biotype, in eight Cucurbita pepo varieties Attractivity, oviposition preference, and nymphal development were evaluated under greenhouse and laboratory conditions Variety Bianca was the least attractive to adult whiteflies in multi-choice tests The whiteflies showed oviposition nonpreference (antixenosis) for Novita Plus, Bianca and Sandy in multi-choice test, and similar results were observed in no-choice tests with varieties Bianca, Novita, Caserta Cac and Sandy Sandy expressed high antibiosis levels against whitefly nymphs, leading to 639% mortality The high level of resistance in variety Sandy can serve as base for genetic improvement of C pepo focusing on the development of resistant varieties to B tabaci B biotype
TL;DR: The results showed that all of A. gossypii from five host plant species used were acceptable for the growth, development and reproduction of H. variegata, however, the suitability of aphids from various host plants was different for this ladybird beetle.
Abstract: The aphidophagous ladybird beetle, Hippodamia variegata (Goeze), is an important predator in many agricultural ecosystems. However, information on the influence of the prey’s host plant species on its life history characteristics is still absent in the literature. Therefore, five host plant species of Aphis gossypii Glover, viz. Cucumis sativus L., Cucurbita pepo var. medullosa L., Cucurbita moschata var. melonaeformis Poiret, Cucumis melo var. cantalupensis L. and Lagenaria siceraria var. gourda Standl., were selected to study the influence of the prey’s host plant species on the development, survival, reproduction and life table parameters of H. variegata in the laboratory at 25°C. The results showed that all of A. gossypii from five host plant species used were acceptable for the growth, development and reproduction of H. variegata. However, the suitability of aphids from various host plants was different for this ladybird beetle. The complete pre-imaginal development was longest (14.51 ± 0.17 days) when reared with aphids on C. melo var. cantalupensis and shortest (12.60 ± 0.11 days) on L. siceraria var. gourda. Total immature survival from egg to adult was highest (58.97%) on L. siceraria var. gourda and lowest (44.06%) on C. melo var. cantalupensis. Based on the intrinsic rate of increase as an index of suitability of prey host plant species on the population increase of H. variegata, the suitability in decreasing order was: L. siceraria var. gourda > C. moschata var. melonaeformis > C. pepo var. medullosa > C. melo var. cantalupensis > C. sativus. This study offered opportunities for better understanding the tritrophic interactions of the plant–aphid–predator relationship.
TL;DR: It is demonstrated that it is accurate to estimate thrips populations using yellow sticky traps (YST) in rose crops in greenhouse and the possibility of setting a damage threshold using the data from the YST in the greenhouse is discussed.
Abstract: The thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is among the most important pests of greenhouse crops in Europe and causes considerable damage to commercial rose crops. The usage of pesticides is associated with major problems, and thus the interest of implementing integrated pest management (IPM) for rose crops is increasing. One essential component of IPM is field monitoring/scouting. Growers use information gathered from scouting to select and schedule appropriate control tactics. Thrips populations were surveyed in 2005 and 2006 in a greenhouse planted with roses, Rosa x Hybrida in Southern of France. From April to August, thrips were counted using yellow sticky traps (YST), knock-down techniques [i.e., tapping flower heads (FT)] and actual counts of entire plants. Thrips abundance recorded using YST correlated well with abundance levels determined through FT or actual counts (whole plant). Our results demonstrate that it is accurate to estimate thrips populations using YST in rose crops in greenhouse. Because YST takes at least twice less time than other monitoring methods, it could be used as a valid and easy monitoring technique in further development of IPM programs on roses. The possibility of setting a damage threshold using the data from the YST in the greenhouse is discussed.
TL;DR: A Pest Risk Analysis was conducted, according to the European and Mediterranean Plant Protection Organization decision support scheme for quarantine pests, to evaluate the risk to Austrian agriculture by M. pruinosa and biological control with its natural enemy Neodryinus typhlocybae is recommended.
Abstract: The North American planthopper Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) was accidentally introduced into Europe, and subsequently caused economic damage to orchards and vineyards in some South-European countries. In 2003, a mass occurrence of M. pruinosa was discovered in Vienna, followed by new infestations of several sites. A Pest Risk Analysis was conducted, according to the European and Mediterranean Plant Protection Organization decision support scheme for quarantine pests, to evaluate the risk to Austrian agriculture by M. pruinosa. The highest risk of further introduction into Austria arises from trade of deciduous plants infested with M. pruinosa eggs from Italy and France where this pest is common and which are important trading partners of Austria. Entry by vehicle traffic is considered moderately likely. Active spread by flight of adult M. pruinosa is considered significant only for local dispersal. The CLIMEX® program was applied to predict M. pruinosa’s potential geographical distribution and to identify areas at risk. In Austria, southern Burgenland and south-east Styria as well as parts of Vienna, Lower and Upper Austria provide the most suitable climate for M. pruinosa’s development. Organic production areas in theses regions are especially at risk of being damaged. To prevent economic impact and for long-term control of M. pruinosa, biological control with its natural enemy Neodryinus typhlocybae (Ashmead 1893) (Hymenoptera: Dryinidae) is recommended.
TL;DR: This is the first report of strobilurins exhibiting high activity against P. halstedii and is a promising fungicide for controlling sunflower downy mildew disease by seed treatment and foliar spray.
Abstract: The efficacy of three commercial formulations of strobilurins, viz., trifloxystrobin, kresoxim-methyl, and azoxystrobin was evaluated against sunflower downy mildew disease caused by Plasmopara halstedii under laboratory, greenhouse, and field conditions. Complete inhibition of sporangial sporulation, zoospore release, and motility was observed with 2 μg ml−1 in trifloxystrobin, and 5 μg ml−1 for azoxystrobin and kresoxim-methyl. Seed treatment with different concentrations of strobilurins enhanced seed germination and seedling vigor of sunflower to varying degrees compared to control. Highest seed germination was recorded at 10 μg ml−1 in kresoxim-methyl, and maximum seedling vigor was noticed with trifloxystrobin at 30 μg ml−1. The effect of strobilurins was tested as seed treatment, foliar application, and seed treatment followed by foliar application. Under greenhouse conditions none of the concentrations used, either as seed treatment and foliar application, were phytotoxic. For the three strobilurins, the seed treatment along with foliar application enhanced the protection of the plants as compared to only the treatment of seeds. Foliar spray treatments alone provided an intermediate control of the disease. Trifloxystrobin showed a better effect than kresoxim-methyl and azoxystrobin. Disease curative activity of trifloxystrobin was higher compared to kresoxim-methyl and azoxystrobin. Tested fungicides when applied on adaxial leaf surface showed partial translaminar activity, and disease inhibition was marginal. Loss of trifloxystrobin and azoxystrobin activity over time was low, indicating stable rainfastness residual activity. A trend in protection against downy mildew disease similar to greenhouse results was evident in the field trials. This is the first report of strobilurins exhibiting high activity against P. halstedii and is a promising fungicide for controlling sunflower downy mildew disease by seed treatment and foliar spray.
TL;DR: Nematodes have the potential to reduce D. v. virgifera larvae in most soils; however, their efficacy can be higher in maize fields with heavy clay or silty clay soils than in sandy soils, which is in contrast to the common assumption that nematodes perform better in sandy soil than in heavy soils.
Abstract: The use of entomopathogenic nematodes is one potential non-chemical approach to control the larvae of the invasive western corn rootworm (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) in Europe. This study investigated the efficacy of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Heterorhabditis megidis Poinar, Jackson and Klein (Rh., Heterorhabditidae) and Steinernema feltiae Filipjev (Rh., Steinernematidae) in reducing D. v. virgifera as a function of soil characteristics. A field experiment was repeated four times in southern Hungary using artificially infested maize plants potted into three different soils. Sleeve gauze cages were used to assess the number of emerging adult D. v. virgifera from the treatments and untreated controls. Results indicate that nematodes have the potential to reduce D. v. virgifera larvae in most soils; however, their efficacy can be higher in maize fields with heavy clay or silty clay soils than in sandy soils, which is in contrast to the common assumption that nematodes perform better in sandy soils than in heavy soils.
TL;DR: The aqueous extract of C. viscosum effectively and significantly reduced the mite population as well as infestation of tea mosquito bug by 68–95% and 73–86%, respectively, and their bioefficacy is comparable to synthetic and neem pesticides.
Abstract: The toxicity of four concentrations (1, 5, 10 and 20% w/v) of an aqueous extract from the weed, Clerodendrum viscosum Ventenat (Verbenaceae) was investigated under field conditions of the North Bengal University, Darjeeling, West Bengal, India for managing two major pests of tea, Camellia sinensis (L), namely the tea mosquito bug, Helopeltis theivora Waterhouse, (Heteroptera: Miridae) and the tea red spider mite, Oligonychus coffeae Nietner, (Acarina: Tetranychidae). Four field trials, two for red spider mite and two for tea mosquito bug, were conducted during April–May 2008 and October–November 2009 following a Randomized Block design. The aqueous extract of C. viscosum effectively and significantly reduced the mite population as well as infestation of tea mosquito bug by 68–95% and 73–86%, respectively, and their bioefficacy is comparable to synthetic and neem pesticides. No phytotoxic effect (score 0–5% and grade 1) was observed in the tea bushes sprayed with different doses of aqueous extract of C. viscosum in the field. Made tea samples were taint free. Organoleptic test revealed leaf-infusions and liquor strength as good, scoring 6.5–7.0 on a 10 point scale. Availability and distribution of this weed (C. viscosum) in and around tea-growing areas of sub Himalayan region, along with its processing for the feasibility of including C. visosum extracts in the current IPM programme is discussed.
TL;DR: Esterase enzymes may be playing a role in chlorpyrifos resistance while glutathione S-transferase (GST) and P450 enzymes do not appear to have any significant involvement.
Abstract: Changes in insecticide susceptibilities and detoxifying enzyme activities were measured in a strain of Tetranychus urticae Koch following repeated exposure to the organophosphate insecticide, chlorpyrifos. Twelve consecutive selection at the LC60 of the parental strain increased resistance from 8.58 to 91.45 fold. The interaction of some synergists [piperonyl butoxide, triphenyl phosphate and S-benzyl-O,O-diisopropyl phosphorothioate (IBP)] with chlorpyrifos was analyzed in the selected strain. Solely IBP showed a low synergistic effect with chlorpyrifos. The selected strain also demonstrated resistance against abamectin, propargite, clofentezine and fenpyroximate. The mode of resistance inheritance to chlorpyrifos was found to be incompletely dominant, and not sex-linked. Non-specific esterase enzyme activity was raised from 19.35 to 33.59 mOD/min/mg proteins during the selection period and it was observed that esterase band intensities visualized by polyacrylamide gel electrophoresis increased. This study has investigated the selection of resistance to chlorpyrifos and documented resistance to abamectin, propargite, clofentezine and fenpyroximate in Turkish T. urticae. Esterase enzymes may be playing a role in chlorpyrifos resistance while glutathione S-transferase (GST) and P450 enzymes do not appear to have any significant involvement.
TL;DR: Phylogenetic analysis indicated that the PCG-1, ECG, and B biotypes clustered into different clades even though they share the same cotton plant species as their host.
Abstract: Bemisia tabaci is a species complex, of which the B and Q biotypes are globally distributed. B. tabaci feeds on more than 600 plant species including cotton, which is one of the main crops in Pakistan. In this study, the biotypes/haplotypes of B. tabaci populations collected from cotton plants in Pakistan, China, and Egypt were identified, and their phylogenetic relationships were investigated. None of the populations from Pakistan or Egypt belonged to the B or Q biotype: all 16 samples from Pakistan belonged to haplotype “PCG-1” and it is a group of unresolved populations all from Pakistan, while all three populations from Egypt belonged to unresolved haplotype “ECG.” The three populations from China belonged to the B biotype. Phylogenetic analysis indicated that the PCG-1, ECG, and B biotypes clustered into different clades even though they share the same cotton plant species as their host. The association between the outbreaks of cotton leaf curl disease and the occurrence of the PCG haplotype of B. tabaci in Pakistan is discussed.
TL;DR: Results from the space fumigation revealed that garlic essential oil and diallyl trisulfide had strong fumigant activities against the adult insect, Tribolium castaneum, and may provide valuable advances for future fumIGant development and possible utility as a fumigsant especially as a seed protectant in warehouses filled with grain.
Abstract: In this study, the fumigant activity of garlic essential oil and its major components, diallyl disulfide, diallyl trisulfide, and diallyl sulfide, against the stored-product insect, Tribolium castaneum, were investigated. Results from the space fumigation revealed that garlic essential oil and diallyl trisulfide had strong fumigant activities against the adult insect. In glass chambers (10 cm in diameter × 125 cm in height) filled with 10, 20, 30, 40, and 50% volume of rough rice, the fumigant activity of diallyl trisulfide was more potent than that of garlic essential oil. At the concentration of 8 μl/l and 50% filling ratio, to obtain 100% mortality, exposure time of only 4 days was needed for diallyl trisulfide, but a longer exposure time (6–7 days) was required for garlic essential oil. Meanwhile, the fumigant effects on the germination rate of kernels exposure were ascertained. Results proved that there were no side effects for these substances on germination rate of kernels exposed 6 months after fumigation. In addition, the fumigant effect on F1 progeny production in rough rice was also evaluated for garlic essential oil and diallyl trisulfide. The results showed that progeny production was totally suppressed at 4 μl/l of these two substances, either at 10 or 50% filling ratio. The results may provide valuable advances for future fumigant development and possible utility as a fumigant especially as a seed protectant in warehouses filled with grain.
TL;DR: There is a great potential for the powder of P. glandulosus as a promising grain protectant for integration within the subsistence farming systems of sub-saharan Africa.
Abstract: Powdered leaves of Clausena anisata and Plectranthus glandulosus were evaluated on Cameroonian and German strains of Sitophiluszeamais and Prostephanus truncatus for their insecticidal activities, the effects on progeny production, grain damage and population increase by admixing powders and maize grains. The two powders caused significant mortality of the three insects with P. glandulosus being far more effective than C. anisata. P. truncatus was less susceptible to P. glandulosus powder compared with the two strains of S. zeamais. The German strain (LD50 = 2.75 g/100 g grain) of S. zeamais was less susceptible to P. glandulosus powder than the Cameroonian strain (LD50 = 1.86 g/100 g grain). P. glandulosus unlike C. anisata powder, considerably reduced grain damage, progeny production and population increase. This study shows that there is a great potential for the powder of P. glandulosus as a promising grain protectant for integration within the subsistence farming systems of sub-saharan Africa.
TL;DR: Laboratory experiments were done to determine the effect of geochemical composition of diatomaceous earth (DE) on insecticidal activity of DE against adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae).
Abstract: Laboratory experiments were done to determine the effect of geochemical composition of diatomaceous earth (DE) on insecticidal activity of DE against adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Samples of DE were mined from DE-deposits in Slovenia, Greece, and Serbia. In addition, a commercially available DE formulation (SilicoSec®) was used in the tests and served as a positive control. The bioassays were carried out at temperatures 20, 25, and 30°C, relative humidity levels of 55 and 75%, and at application rates of 100, 300, 500, and 900 ppm. Adult mortality was recorded after 7, 14, and 21 days of exposure. Prior to bioassays with S. oryzae, the geochemical composition of all DEs that were used in the tests was determined by whole rock ICP geochemical analyses. Silica (in the form of SiO2 or opal-A) was the DE ingredient that was significantly correlated with efficacy in most of the bioassays. Some weak positive correlation was observed between S. oryzae mortality and MnO or CaO content. All significant correlations between mortality and Al2O3, Fe2O3, K2O, TiO2, Cr2O3, P2O5, and MgO content were negative, while correlation between Na2O content and mortality was generally not significant.
TL;DR: This study revealed that HRE offers a natural and effective extract to control grey mould and possessed a similar disease severity reduction than HROMW.
Abstract: Olive mill wastewater (OMW) is a rich source of antifungal agents and has a merit as alternative to synthetic fungicides. To develop disease control agents against Botrytis cinerea, a hydroxytyrosol-rich (29.27% weight:dry weight) olive mill wastewater (HROMW) and a hydroxytyrosol-rich (52.67% weight:dry weight) extract (HRE) were prepared from fresh OMW using hydrolysis and post-hydrolysis purification processes. The HROMW and HRE showed strong fungicidal activity against B. cinerea with minimal fungicidal concentrations (MFCs) of 14.36–28.72 and 28.72–57.44 mg l−1 (dry weight), respectively. According to EN 1275: 1997 standard method, HROMW and HRE at 1.25% (dry weight:volume) showed powerful disinfectant properties resulting in a reduction in the viability of B. cinerea spores by >4 log units after 30 min of contact time. The HROMW or HRE foliar spray treatments, of the B. cinerea inoculated tomato plants, resulted in disease control percentage of 95 and 91%, respectively, whereas 70% was conferred by benomyl treatment. Although, HRE possessed a similar disease severity reduction than HROMW, it showed great advantage by fortifying plants and by improving their growth and healthy aspect. Indeed, HRE-treated plants showed significantly better: (i) plant height (146.2 and 130.5%), (ii) average stem diameter (135% and 110%), (iii) leaf number (163.6 and 128.5%), and (iv) leaf colour (chlorophyll a content) (144.4 and 103%) than benomyl-treated and non-treated plants, respectively. This study revealed that HRE offers a natural and effective extract to control grey mould.
TL;DR: In this article, different azadirachtin concentrations were evaluated at different doses against the H. theivora to find out their controlling efficacy, and the results showed that at 50,000 and 10,000ppm, 65% and 30% control of infestation could be attained, whereas at 3,000, 10, 000, and 300 and 1,500 ppm <30% control was possible.
Abstract: Despite continuous use of synthetic insecticides during last two decades, the tea mosquito bug, Helopeltis theivora Waterhouse (Miridae: Heteroptera), has become the most destructive sucking pest of tea in North East India. In order to reduce the load of the synthetic chemicals in tea vis-a-vis their deleterious effect, integration of biopesticide, synthetic pesticides along with effective spraying strategies, have been attempted. The anti-insect property of “neem”, Azadirachta indica A. Juss. (Meliaceae), has been used to solve many pest problems. In this study, different azadirachtin concentrations were evaluated at different doses against the H. theivora to find out their controlling efficacy. At 50,000 ppm azadirachtin concentration 65% control of infestation could be attained, whereas at 3,000 and 10,000 ppm, gave 30–43% reduction and 300 and 1,500 ppm <30% control was possible. Further in case of 3,000 and 10,000 ppm, azadirachtin concentration 30–43% reduction was registered. Therefore, azadirachtin concentration and its dilutions are the major criteria for getting desired bioactivity. Treatments with combined formulations viz. “neem + endosulfan” or “neem + deltamethrin” recorded significant reduction in H. theivora incidence even at reduced doses, as compared to sole application of neem or synthetic insecticide at recommended doses. Effective combinations and dose of the insecticides along with their formulations in controlling H. theivora have been presented and discussed.
TL;DR: B. bassiana EC (strain PPRI 5339) appears to be the most promising product to promote an IPM programme in South Africa due to the good performance and low risk to humans and environment.
Abstract: Toxicity by contact and by ingestion of lufenuron, flufenoxuron, lambda (λ)-cyhalothrin, cypermethrin, thiamethoxam and five entomopathogenic insecticides (three formulations of Beauveria bassiana, a compound containing spores of Metarhizium anisopliae var. acridum, and a mixture of Brevibacillus laterosporus, Bacillus licheniformis and Bacillus chitinosporus) were evaluated on adults of the Eucalyptus snout-beetle Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae) under laboratory conditions. By contact, entomopathogenic fungus B. bassiana EC and the pyrethroid λ-cyhalothrin exhibited the highest efficiency, achieving 100 and 97.5% mortality, respectively. By ingestion, the highest mortality was obtained by B. bassiana EC (100%) and thiamethoxam (95%). Flufenoxuron and lufenuron, bacteria mixture and M. anisopliae showed a weak toxicity. Furthermore, we found a sex-biased mortality, being males more affected. Due to the good performance and low risk to humans and environment, B. bassiana EC (strain PPRI 5339) appears to be the most promising product to promote an IPM programme in South Africa.
TL;DR: The management of M. hapla using plant essences seems to be possible, however, further research is desirable to determine the appropriate dosage needed for efficient and most appropriate delivery method of these substances under field conditions.
Abstract: The northern root-knot nematode (Meloidogyne hapla) is a prominent root vegetable pest in the Czech Republic. Effects of several plant essences for M. hapla management on carrot (Daucus carota) were tested. The tested compounds included commercially available plant essences from Ocimum basilicum (sweet basil), Mentha arvensis (field mint), Tageteserecta (Mexican marigold), and commercial product of neem seed (Azadirachtaindica). Two further essences from Eugenia caryophyllata (clove) and Origanum majorana (marjoram) were obtained by distillation. Tests were conducted on container-grown carrots maintained under field conditions. The delivery method involved absorbing the tested essences in perlite particles placed in a substrate. The results showed a negative correlation between gall numbers of the carrots and treatment concentrations, especially for clove and majoram. Similar results were achieved when considering M. hapla egg numbers. Furthermore, the same treatments showed significant differences (P ≥ 0.05) in fresh and dry root weights. Based on these results the management of M. hapla using plant essences seems to be possible, however, further research is desirable to determine the appropriate dosage needed for efficient and most appropriate delivery method of these substances under field conditions.