Showing papers in "International Journal of Pest Management in 1994"
TL;DR: It is concluded that research on control strategies is urgently needed but requires sound knowledge of the ecology of the snail in its natural habitat.
Abstract: The golden apple snail, Pomacea canaliculata (Lamarck, 1822) (Mesogastropoda: Pilidae), has recently been introduced to several Asian countries where it has unexpectedly developed into a pest of rice Reasons for the introduction as well as the economic and ecological impact of the snail are described Most farmers have resorted to chemical control, with implications for human health and the environment Integrated snail management practices are summarized including the use of the snail as a valuable aquatic resource It is concluded that research on control strategies is urgently needed but requires sound knowledge of the ecology of the snail in its natural habitat
221 citations
TL;DR: The parthenogenetic nature of reproduction and the surprising degree of variability seen in populations from different locations in the UK are seen, both in the industrial and domestic setting.
Abstract: Over the last 30 years the booklouse, Liposcelis bostrychophila has become an increasingly common domestic pest of stored food products. This review draws together published and unpublished information on the biology, population dynamics, and physiology of this species. The current pest status of L. bostrychophila in the UK and elsewhere is described. Emphasis is given to the parthenogenetic nature of reproduction and the surprising degree of variability seen in populations from different locations in the UK. A variety of approaches to the management of booklice as pests are explored, both in the industrial and domestic setting. Tolerance to pyrethroid insecticides has been found in some populations and is identified as a potential problem in current control practices.
130 citations
TL;DR: The majority of pesticide applications by rice farmers in the Mekong Delta, Vietnam, and Leyte, Philippines, were insecticides, and high proportions of the sprays were targeted at leaf‐feeding insects.
Abstract: The majority of pesticide applications by rice farmers in the Mekong Delta, Vietnam, and Leyte, Philippines, were insecticides. Farmers in Vietnam applied more insecticides per season (∼6.1 sprays) than Filipino farmers (∼2.6 sprays). About half of the insecticide sprays were organophosphates and the main chemicals were methyl parathion, monocrotophos, and methamidophos. About 22% and 17% of the chemicals in the Philippines and Vietnam, respectively, were classified as ‘extremely hazardous’ (Category la) by the WHO. Another 17% and 20% in the Philippines and Vietnam, respectively, were classified as ‘highly hazardous’ (Category Ib). High proportions of the sprays were targeted at leaf‐feeding insects which accounted for 42% and 28% of insecticide sprays in Vietnam and Philippines, respectively. In the Philippines, sprays against rice bugs accounted for 44% while in Vietnam, those against brown planthoppers accounted for 34%. Since research has shown that leaf feeder control generally does not inc...
96 citations
TL;DR: Although the importance of Panama disease decreased after the Cavendish cultivars replaced Gros Michel, recent outbreaks have renewed interest in this problem and attention is drawn to affected non‐exported bananas which are important cash crops or staple foods.
Abstract: Before 1960, Panama disease (fusarium wilt) was the most important disease in the banana export trades. Although the importance of Panama disease decreased after the Cavendish cultivars replaced Gros Michel, recent outbreaks have renewed interest in this problem. Race 4 affects cultivars of the Cavendish subgroup in the subtropics, as well as race 1 and race 2 suscepts. It has caused concern in the tropically based export trades which depend almost entirely on the Cavendish clones. Attention is also drawn to affected non‐exported bananas which are important cash crops or staple foods. Although they are not as well documented as those on the Cavendish subgroup, epidemics of the disease on non‐exported bananas are far more important.
85 citations
TL;DR: Pithraj seed extracts were moderately toxic to rice weevils and an ethanol extract was the most toxic of four extracts tested and showed the lowest LD50 and LT50 values.
Abstract: Crude seed extracts of pithraj, Aphanamixis polystachya were evaluated fortheir repellency, feeding deterrency, contact toxicity and oviposition deterrency to rice weevils. The extracts had strong repellent and feeding deterrent effects on rice weevils. Pithraj seed extracts were moderately toxic to rice weevils. An ethanol extract was the most toxic of four extracts tested and showed the lowest LD50 and LT50 values. The ground leaves, bark and seeds at a 2.5% ratio provided good protection for rice grains by reducing the F1 progeny emergence and the grain infestation rates.
78 citations
TL;DR: Field trials proved that a dosage of 2 g/m3 with 10 days’ exposure and a terminal concentration exceeding 0.5 g/ m3 was effective against all stages of the phosphine‐resistant strains, and Repeated phosphine treatments under leaky situations, especially with tarpaulins of poor gas retention, resulted in a high level of resistance.
Abstract: Survivalship of the life stages of the cigarette beetle, Lasioderma serricorne F. (Coleoptera: Anobiidae), was recorded in tobacco bales that were fumigated under a gas‐proof cover with phosphine at the rate of 1–1.25 g/m3 for 7 or 8 days with the terminal concentration at > 0.1 g/m3 in warehouses at Ongole, Andhra Pradesh, India. Screening tests at the discriminating concentration of 0.07 g/m3 with a 24‐h exposure period confirmed the occurrence of phosphine‐resistant strains in the premises. Repeated phosphine treatments under leaky situations, especially with tarpaulins of poor gas retention, resulted in a high level of resistance. Field trials proved that a dosage of 2 g/m3 with 10 days’ exposure and a terminal concentration exceeding 0.5 g/m3 was effective against all stages of the phosphine‐resistant strains. During fumigation of tobacco packed in gunny bales with wooden bale boards, phosphine concentrations between the freespace in the stack and inside the bales equilibrated in 24 h, whils...
75 citations
TL;DR: In areas with regular cultivation of tomatoes, the population densities of all species of nematodes, regardless of trophic group, were high, and endophytic fungi were frequently isolated from tomato roots, with Fusarium oxysporum being the most common endophyte detected.
Abstract: The occurrence of plant parasitic nematodes and endophytic fungi in tomato plants was determined from different regions in Kenya. In areas with regular cultivation of tomatoes, the population densities of all species of nematodes, regardless of trophic group, were high. Meloidogyne incognita was the predominant plant parasitic nematode in the regions investigated. Apparently endophytic fungi were frequently isolated from tomato roots, with Fusarium oxysporum being the most common endophyte detected. In contrast, irregular cultivation of tomato resulted in lower overall nematode densities and the absence of Meloidogyne infestation. F. oxysporum occurred only sporadically. Four isolates of F. oxysporum which were tested in subsequent greenhouse experiments, reduced M. incognita populations without adversely affecting plant health. Non‐pathogenic isolates of F. oxysporum with mutualistic symbiotic behaviour are potential biological control agents for plant parasitic nematodes.
60 citations
TL;DR: Insecticide‐impregnated paper assays were used to analyse the inheritance of Deltamethrin resistance in a DDT‐pyrethroid cross‐resistant strain of maize weevil, Sitophilus zeamais Mots, from Brazil and provided evidence that a single gene was responsible for resistance.
Abstract: Insecticide‐impregnated paper assays were used to analyse the inheritance of Deltamethrin resistance (2634X) in a DDT‐pyrethroid cross‐resistant strain of maize weevil, Sitophilus zeamais Mots., from Brazil. At the KD50 the responses of the F1hybrid reciprocal crosses were very different and χ2 analyses of the observed responses of F2 and F1‐backcross progenies provided evidence that a single gene was responsible for resistance. Deltamethrin resistance seems to be controlled by a single recessive sex‐linked gene.
56 citations
TL;DR: It was found that the major rice pests, as perceived by farmers, are weeds, vertebrates (birds and rodents) and insects, and implications are derived for an integrated pest management strategies.
Abstract: An understanding of fanners’ perceptions of pests and their existing pest control methods can make an important contribution to the development of effective integrated pest management strategies. While the relatively successful rice IPM technologies in Asia have been extensively documented in studies examining farmers’ pest perceptions and management practices, studies examining, specifically, perceptions and management practices of West African rice farmers are rare. This may reflect the more limited success to date in the implementation of rice IPM strategies in the region. This paper describes rice pests, pest perceptions and management practices of smallholder rice farmers in the Ivory Coast. It was found that the major rice pests, as perceived by farmers, are weeds, vertebrates (birds and rodents) and insects. Farmers are generally unable to diagnose rice plant diseases and thus did not consider them as important production constraints. Implications are derived for an integrated pest managem...
50 citations
TL;DR: Nine viruses which can infect solanaceous crops were detected and transmission of PVY and ToMV from S. viarum produced a range of symptoms in pepper, tobacco, and tomato.
Abstract: Solanum viarum Dunal (tropical soda apple), an introduced and rapidly spreading weed, currently infests over 60 000 ha in Florida. Approximately 220 plants were sampled in seven stands of S. viarum in south‐west and west central Florida during 1992 and 1993 to determine the occurrence of nine viruses which can infect solanaceous crops. Virus detection utilized a double antibody sandwich‐enzyme linked immunosorbent assay, or a nucleic acid spot hybridization assay. The viruses detected included cucumber mosaic virus (CMV), potato leaf roll virus (PLRV), potato virus Y (PVY), tobacco etch virus (TEV), tomato mosaic virus (ToMV), and tomato mottle virus (TMoV). Transmission of PVY and ToMV from S. viarum produced a range of symptoms in pepper, tobacco, and tomato. Isolates of TEV from pepper, and PVY and TMoV from tomato were transmitted to S. viarum. Solanum viarum was also naturally infected in the field by Altemaria solani Sorauer and infested by Colorado potato beetles (Leptinotarsa decenlineata...
50 citations
TL;DR: All the insecticide formulations effectively controlled Megalurothrips sjostedti and Maruca testulalis but biphenthrin was slightly inferior to the rest of the insecticides in the control of Clavigralla spp.
Abstract: Two formulations of standard insecticides, cypermethrin + dimelhoate were compared with newly formulated insecticides, namely α‐cypermethrin, biphenthrin, λ‐cyhalothrin, λ‐cyhalothrin + dimethoate and λ‐cyhalothrin + pirimicarb for the control of insect pests of cowpea. All the insecticide formulations effectively controlled Megalurothrips sjostedti and Maruca testulalis but biphenthrin was slightly inferior to the rest of the insecticides in the control of Clavigralla spp. The grain yields were not significantly different with respect to insecticide treatments, although, λ‐cyhalothrin + dimethoate (Karata super ed.) produced the highest yields.
TL;DR: Results indicated that use of African tall variety of marigold cv.
Abstract: The possibility of using okra, field bean, pigeon pea, sunflower, maize and marigold as trap crops for the management of the fruit borer Helicoverpa armigera (Hubner) on tomato was evaluated. Initial experiments involved observational row trials with simultaneous planting/seeding of both tomato and trap crops in exploded blocks. One row of these crops was raised on either side and parallel to 10 and 15 rows of tomato respectively. Results indicated that use of African tall variety of marigold cv. Golden Age afforded maximum reduction of both eggs and larvae of H. armigera in the intercropped tomato with a consequent reduction in the number of bored fruits. The rest of the crops were ineffective because they were less preferred and also because flowering in these crops did not synchronize with tomato. Based on the success in observational row trials, systematic studies involving planting combinations of 10, 12, 14, 16, 18 and 20 rows of tomato were evaluated with one row of marigold planted on eit...
TL;DR: One‐week‐old traps made from split banana pseudostems were 1.5–1.7‐fold more attractive to adult banana weevils than 2–3‐week-old traps, and may be effective in weevil control in small‐farm situations where labour avail...
Abstract: One‐week‐old traps made from split banana pseudostems were 1.5–1.7‐fold more attractive to adult banana weevils than 2–3‐week‐old traps. In one experiment, all available pseudostem material was used for trapping, and weekly collecting of weevils over an 11‐month trapping period led to a 50% reduction in weevil catches in one field. In another field with a lower initial weevil density the trapping did not reduce weevil populations. In another experiment, the effect of intensive use of pseudostem traps and daily collecting of trapped weevils was estimated by a mark and recapture method over a period of 6 weeks. Reductions in weevil densities were calculated using a modified version of the Lincoln‐Index. Weevil populations were reduced by 48.5% after 3 weeks and by 62.5% after 6 weeks. Trapping efficiency declined during the experiment and appeared to be related to weevil population densities. This cultural control system may be effective in weevil control in small‐farm situations where labour avail...
TL;DR: This paper suggests an approach based on a collective understanding of the problem and collective action for controlling Striga in the context of the present land tenure system, as other factors limiting the large‐scale adoption of Striga control methods in the region.
Abstract: Striga control methods have been developed to alleviate labour constraints yet smallholder farmers in the West African Semi‐Arid Tropics have been unsuccessful in adopting them. One reason for the low adoption has been the non‐availability of economically feasible and effective techniques that are adapted to local conditions. This paper suggests further constraints, namely the lack of relevant information, e.g. on the economic threshold level that could guide Striga control decision making, and the present land tenure system (where individuals only have usufruct rights to land), as other factors limiting the large‐scale adoption of Striga control methods in the region. It suggests an approach based on a collective understanding of the problem and collective action for controlling Striga in the context of the present land tenure system.
TL;DR: Significant correlations between seed damage and cumulative number of insect days (CD) during pod formation was found for all three groups and for PSBs alone, the CD values were significantly correlated with seed damage.
Abstract: Three insect groups, known from the literature, were confirmed to make up a seed pest complex in cowpea fields in Benin Republic (West Africa) Several species of heteropteran pod‐sucking bugs (PSBs), two lepidopteran species, namely Maruca testulalis (Geyer) and Cydia ptyehora (Meyrick) and the weevil Apion varium Wagner occurred throughout southern Benin Field infestations of PSBs and M testulalis were always present, whereas A varium and C ptyehora occurrence was sporadic Seed damage assessment at harvest time showed that in 80% of 25 fields, planted between 1990 and 1992, PSBs were the most important pests PSB damage to seed usually ranged between 40 and 85% Seed damage from M testulalis was low, despite occasional high flower infestations C ptyehora was a minor pest in all locations Significant correlations between seed damage and cumulative number of insect days (CD) during pod formation was found for all three groups For PSBs alone, the CD values were significantly correlated w
TL;DR: Thiodicarb, fenvalerate and abamectin tended to be less detrimental to at least some life stages of both parasitoids compared with methomyl, permethrin, methamidophos or endosulfan, and generally were the least toxic to all life stages, especially of D. intermedius.
Abstract: Adults, larvae and pupae of Diglyphus intemedius (Girault) and Neochrysocharis punctiventris (Crawford), (Hymenoptera: Eulophidae), parasitoids of the leaf‐miner Liriomyza trifolii (Burgess) (Diptera: Agromyzidae), were exposed to methomyl, permethrin, methamidophos, thiodicarb, endosulfan, fenvalerate, abamectin, Bacillus thuringiensis var. kurstaki and cyromazine in the laboratory. Permethrin and methomyl were highly toxic to all life stages of both parasitoids while methamidophos was highly toxic to adults but was less toxic to larvae and pupae. Endosulfan tended to be highly toxic to N. punctiventris but less toxic to D. intermedius. Thiodicarb, fenvalerate and abamectin tended to be less detrimental to at least some life stages of both parasitoids compared with methomyl, permethrin, methamidophos or endosulfan. B. thuringiensis and cyromazine generally were the least toxic to all life stages, especially of D. intermedius. The implications for field identification of leaf‐miner parasitoids in...
TL;DR: Results of this trial and of a greenhouse experiment were unable to show that the nematode Hoplolaimus pararobustus was pathogenic to either plantain or banana.
Abstract: Microplots were prepared in land infested with the banana nematode Radopholus similis and the banana weevil, Cosmopolites sordidus. For 1 year, one of six crops was grown in the microplots or the microplots were left fallow. Sampling showed that in addition to plantain (Musa AAB) both maize and groundnut were hosts to R. similis. After a year microplots were replanted with tissue‐cultured plantain. Three months after planting, tissue‐cultured plantain in plots that previously supported plantain, maize and groundnut were heavily infested with R. similis. Thirteen months after planting, tissue‐cultured plantain showed best growth in previously‐bare‐fallow plots with poorest growth in previously‐plantain plots. Damage by C. sordidus was severe in previously‐plantain plots but much less so in other plots. Results of this trial and of a greenhouse experiment were unable to show that the nematode Hoplolaimus pararobustus was pathogenic to either plantain or banana. Recommendations are made for the mana...
TL;DR: Sclerotium rolfsii‐caused stem and pod rots are major constraints to groundnut production in many groundnut‐growing regions, and pose a serious threat to post‐rainy and summer season groundnuts in expanding irrigated production systems.
Abstract: Sclerotium rolfsii‐caused stem and pod rots are major constraints to groundnut production in many groundnut‐growing regions, and pose a serious threat to post‐rainy and summer season groundnuts in expanding irrigated production systems. Considerable research has been carried out on the management of these diseases. The most relevant literature is reviewed and future research strategies are indicated.
TL;DR: Application of the fungicides Captan, Fenpropimorph, Carbendazim, Mancozeb, and Propiconazole significantly reduced the area under the tar spot disease progress curves, which in turn significantly increased grain yields.
Abstract: The tar spot disease complex of maize and the effects of fungicides on disease development were examined during the November‐April 1988 cropping season in Mexico. The disease is caused by two fungi, Phyllachora maydis Maublanc and Microdochium maydis Muller & Samuels (teleomorph = Monographella maydis Muller & Samuels). The ascostromata of P. maydis can be observed on the lower leaves of the plants generally 10–18 days before silking. M. maydis the second fungus involved in the complex, was found in infected tissues 10–14 days after ascostromata formation. Lesions subsequently enlarged, appeared water‐soaked, and coalesced to cause leaf blight. Application of the fungicides Captan, Fenpropimorph, Carbendazim, Mancozeb, and Propiconazole significantly reduced the area under the tar spot disease progress curves, which in turn significantly increased grain yields. Fenpropimorph resulted in the lowest overall disease severity but not the highest yield. Disease severity in plants sprayed with Mancozeb...
TL;DR: The percentage of trees damaged decreased significantly with increased distance from the rainforest edge, and damaged trees were distributed non‐randomly (clumped) throughout the plot.
Abstract: Damage by the banana‐spotting bug, Amblypelta lutescens lutescens to papaw trees was assessed at 12 sites in North Queensland. Sites were chosen to determine if the number of damaged trees differed between plots grown adjacent to remnant rainforest or plots grown in open areas. Regression analysis was used to examine the relationship between distance from the forest edge and percent damage. To gain insight into A. I. lutescens behaviour, the spatial distribution of damaged trees was mapped. Papaw trees in sites that bordered remnant rainforest were attacked more frequently than those in open areas. The percentage of trees damaged decreased significantly with increased distance from the rainforest edge, and damaged trees were distributed non‐randomly (clumped) throughout the plot. The distribution of damaged trees suggests short flights and indicates more information is needed on dispersal characteristics. Damage by A. /. lutescens to male and female trees was not significantly different.
TL;DR: Most isolates of Colletotrichum gloeosporioides obtained from anthracnose lesions on mango leaves, inflorescences and fruits from different regions in Sri Lanka showed the same ribosomal DNA (rDNA) and very similar mitochondrial DNA (mtDNA) restriction fragment banding patterns when genomic DNA was digested with endonuclease EcoR I.
Abstract: Most isolates of Colletotrichum gloeosporioides (>80%) obtained from anthracnose lesions on mango leaves, inflorescences and fruits from different regions in Sri Lanka showed the same ribosomal DNA (rDNA) and very similar mitochondrial DNA (mtDNA) restriction fragment banding patterns when genomic DNA was digested with endonuclease EcoR I This rDNA restriction fragment banding pattern was the same as that revealed by C gloeosporioides isolates from mango in other tropical countries Isolates obtained from inflorescences all showed the same rDNA and mtDNA restriction patterns but a few isolates from fruits and leaves from mango grown in mixed orchards in areas of Sri Lanka with two monsoons and year‐round rainfall had rDNA restriction patterns associated with isolates from other fruit crops This suggested that some cross‐infection onto mango occurs However, it is suggested that there is a strain of C gloeosporioides specific to mango and the clonal nature of this strain implies that it has di
TL;DR: Twenty‐two medicinal plant powders, ash of plant origin and sorbic acid were evaluated as grain protectants against Rhizopertha dominica and rauwolfia serpentina completely inhibited feeding and F1 progeny production.
Abstract: Twenty‐two medicinal plant powders, ash of plant origin and sorbic acid were evaluated as grain protectants against Rhizopertha dominica (F.). Rauwolfia serpentina sorbic acid, Acorus calamus, Messua ferrea and Alblzia lebbeck were found effective at 1 % (w/w) in a first screening test and all these products were further assessed at 0.25, 0.5 and 1.0% (w/w). Rauwolfia serpentina completely inhibited feeding and F1 progeny production whereas sorbic acid inhibited infestation by more than 85% and F1 progeny production by 93% even at a concentration of 0.25%. Messua ferrea and A. calamus achieved more than 80% suppression at 0.50%. Albizia lebbeck exerted appreciable control at 1%.
TL;DR: Most isolates significantly inhibited the growth of Armillaria but the highest inhibition was noted with one of the isolates of T. koningii, T. longibrachiatum and T. harzianum.
Abstract: The interaction of 11 Trichoderma isolates against Armillaria root rot fungus of tea was investigated. Most isolates significantly inhibited the growth of Armillaria. The highest inhibition was noted with one of the isolates of T. koningii, T. longibrachiatum and T. harzianum. The isolates with highest inhibitory properties tended to produce a pigment into the nutrient broth. The implications of these results in view of the future management strategies of Armillaria root rot of tea in Kenya are discussed.
TL;DR: Emerged Striga densities in subsequent years were generally not significantly affected by previous herbicide treatments, and one major source of variation in Striga density in the first year following the Striga suppression treatments was plot variation.
Abstract: Striga hermonthica is an important cause of yield loss in sorghum in the semi‐arid zone of Africa. Two trials were conducted in northern Cameroon to evaluate the effect of herbicides for two cropping seasons on densities of emerged Striga in treatment years and on densities of Striga seed and plants in subsequent years. Herbicide application using 2,4‐D, triclopyr, paraquat, and bromoxynil and urea solution (20%) was compared with hand‐weeding of Striga and an unweeded control. Reduction of emerged Striga density was greatest with 2,4‐D and triclopyr. Sorghum grain yield was greatest in the urea solution treatment. Subsequent (third‐year) Striga seed densities were not significantly different, although they were substantially lower in the 2,4‐D‐treated plots. Emerged Striga densities in subsequent years were generally not significantly affected by previous herbicide treatments. One major source of variation in Striga density in the first year following the Striga suppression treatments was plot p...
TL;DR: The fungus Colletotrichum gloeosporioides was isolated from 23 fruit crops in Sri Lanka and had not been recorded previously on durian, mangosteen, pini jambu and rambutan and 11 other less economically important fruit trees.
Abstract: The fungus Colletotrichum gloeosporioides was isolated from 23 fruit crops in Sri Lanka. This pathogen had not been recorded previously on durian, mangosteen, pini jambu and rambutan and 11 other less economically important fruit trees in Sri Lanka. Symptoms of infection by C. gloeosporioides on fruit tree seedlings, especially mango and rambutan, which can cause up to 40% loss of planting stock, were previously believed to be a physiological disorder. Protection of these seedlings from major sources of C. gloeosporioides inoculum is recommended.
TL;DR: Plantain in the Meander belts zone (the Central Niger Delta area) was less infected by BLS than in the Coastal plain sands (the east of the Niger delta), and plantain grown in homestead gardens had a much lower BLS severity than that planted in field‐plots.
Abstract: Plantain (Musa spp., AAB group) is a staple food crop in the humid forest regions of West and Central Africa. Its cultivation is threatened by black leaf streak (BLS), an air‐borne fungal leaf spot disease, caused by Mycosphaerella fijiensis Morelet. An on‐farm survey for BLS severity in relation to soil fertility was conducted in two different geomorphological zones, the main plantain‐growing areas of Rivers State where plantain is mostly cultivated in compound gardens and in outlying fields mixed with other food crops. Plantain in the Meander belts zone (the Central Niger Delta area) was less infected by BLS than in the Coastal plain sands (the east of the Niger delta). In addition, plantain grown in homestead gardens had a much lower BLS severity than that planted in field‐plots. The host plant response is attributable to the difference in soil fertility both between the two geomorphological zones and between the two farming systems. Therefore, the success of a system would depend on managing ...
TL;DR: An examination of within site variation in damage dispersion suggested that single point or transect assessment of variation provided a reliable estimate of damage over a limited area, however, there was a marked temporal effect on estimation efficiency.
Abstract: Damage caused by the pine weevil (Hylobius abietis) to recently planted Sitka spruce (Picea sitchensis [Bong.] Carr.) was assessed at 82 forest sites in Northern Ireland. Adult weevil numbers were estimated at each site by billet trapping. An examination of within site variation in damage dispersion suggested that single point or transect assessment of variation provided a reliable estimate of damage over a limited area. However, there was a marked temporal effect on estimation efficiency. Variation in damage between sites and weevil abundance was related although much intrasite variation remains unexplained.
TL;DR: The suitability of entomopathogenic organisms as part of a suite of control measures in integrated pest management schemes in forestry is critically reviewed, with particular reference to the contrast between these organisms and chemical control methods.
Abstract: The suitability of entomopathogenic organisms as part of a suite of control measures in integrated pest management schemes in forestry is critically reviewed. The use of fungi, viruses, bacteria, protozoa and nematodes as control agents of forest insect pests is discussed with particular reference to the contrast between these organisms and chemical control methods. In general entomopathogenic organisms are environmentally more suitable than the latter and, although currently more expensive in monetary terms, are in the long run less expensive in terms of deleterious side effects such as human health hazards and destruction of non‐target organisms. The fact that many of these organisms are able to persist in the environment, despite their target organisms being at low levels, also makes them more attractive to use than conventional insecticides. The considerations that need to be given before using such organisms, and future developments, are discussed. The use of entomopathogenic fungi and bacul...
TL;DR: Les pullulations precoces d'Aphis gossypii etaient anciennement negligeables en Afrique centrale, mais elles affectent maintenant les cultures de coton des le debut du cycle de developpement vegetatif.
Abstract: Les pullulations precoces d'Aphis gossypii etaient anciennement negligeables en Afrique centrale, mais elles affectent maintenant les cultures de coton des le debut du cycle de developpement. Quatre annees d'essais de protection des cultures ont montre que ces pullulations provoquent un retard dans le developpement vegetatif ainsi qu'une perte de 5 a 23 % de production de graines de coton. Aphis gossypii est donc un des principaux ravageurs dans cette partie du monde. Le semis precoce apparait comme le plus efficace des moyens de lutte. Pour les semis tardifs, c'est la protection insecticide des graines qui semble la meilleure methode de lutte
TL;DR: It is considered that integration of selected management options is most likely to provide maximum benefit and scaring, repellents and the provision of alternative food sources could provide the most successful long‐term management.
Abstract: Following declining numbers in some areas in the 1980s, Mute Swan numbers have shown a marked increase in recent years. In some areas, such as the Wylye Valley in Wiltshire, this increase has been accompanied by complaints of damage caused to farming and fishing interests. The population dynamics of this population of Mute Swans is described, including its habitat preferences, and these findings are related to possible management options. As the Wylye catchment already receives immigrants from unknown sources, culling and translocation are not appropriate solutions to prevent agricultural damage. A combination of scaring, repellents and the provision of alternative food sources could provide the most successful long‐term management. Whilst different techniques may be needed to resolve the fishing problem, it is considered that integration of selected management options is most likely to provide maximum benefit.