Showing papers in "Environmental Entomology in 1974"
TL;DR: The data contradict the previous belief that this species releases no inhibitor and depends upon host-oleoresin effects to stop beetle aggregation and may help answer certain questions about bark beetle behavior of practical significance in attempts to utilize these pheromones in control.
Abstract: Eight pheromones were collected as volatiles from living Dendroctonus beetles, and identified by GLC/MS. With Dendroctonus frontalis Zimmerman, in addition to earlier reported pheromones, the monoterpene ketone pinocarvone, and frontalin, were released by males, and the terpene alcohol myrtenol was released by both males and females. With D. ponderosae Hopkins, besides the previously known pheromones, endo -brevicomin and 3-methyl-2-cyc1ohexen-1-one (MCH) were released by males, and frontalin was collected from pairs of this species. Bioassay indicated that exo -brevicomin with D. ponderosae , and myrtenol as well as verbenone with D. frontalis , are multifunctional pheromones, since a small quantity (released by females) was synergistically attractive, and a larger quantity (released by males) was repressive and/or evoked “rivalry” behavior. For this latter effect, the male pheromones were designated antiaggregative-“rivalry” pheromones. With D. ponderosae , our data contradict the previous belief that this species releases no inhibitor and depends upon host-oleoresin effects to stop beetle aggregation. The identified male pheromones were released with males placed together, as well as with pairs, and the pheromones of fmale D. frontalis (though not of female D. ponderosae ) were also released with females placed together, as well as with pairs. Both intrasex and intersex stimuli and response must be important in pheromone release, and may help answer certain questions about bark beetle behavior of practical significance in attempts to utilize these pheromones in control.
144 citations
TL;DR: Nine fungicides and 14 insecticides and acaracides were tested in vitro on various isolates of the entomopathogenic fungi, Beauveria bassiana, Verticillium lecanii and Verticillsium sp.
Abstract: Nine fungicides and 14 insecticides and acaracides were tested in vitro on various isolates of the entomopathogenic fungi, Beauveria bassiana , Verticillium lecanii and Verticillium sp. Two techniques were employed: for Verticillium, a “poisoned-bait” method, showing growth inhibition; for B. bassiana , a poisoned-agar disc method, showing inhibition of conidial germination.
All chemicals except white summer oil caused some inhibition to Verticillium growth at 10−4 of the recommended dosages for use.
Great variations in sensitivity toward a particular fungicide (e.g., captan, copper oxychloride, dinocap, binapacryl) were found among isolates of the same fungal species of both genera, and were also observed with some insecticides (e.g., trichlorfon and narrow-range paraffinic oil on Verticillium ).
Among the fungicides, benomyl (methyl 1-[butylcarbamyl]-2-benzimidazole carbamate) and maneb caused the greatest inhibition of all isolates of both genera at recommended dosages and at 10−1 concn, indicating that their use in field or grove would endanger the fungi. At recommended dosages, copper oxychloride and dinocap were the most innocuous to all the fungi (with the exception of 1 isolate of B. bassiana ). Binapacryl had no effect on spore germination of B. bassiana but moderately inhibited growth of most isolates of Verticillium spp. Daconil 2787™ (tetrachloroisophthalo-nitrite) proved moderately fungitoxic to Verticillium and less so to B. bassiana .
Among insecticides, sodium fluorosilicate, dichlorvos, and chloropyrifos at recommended dosages were strongly inhibitory to growth of Verticilium spp., but only sodium fluorosilicate inhibited germination of B. bassiana .
83 citations
TL;DR: A P-generation of female Tetranychus urticae Koch kept on residues of a 200 ppm spray of carbaryl, 100 ppm DDT, and 25 ppm dioxacarb showed significantly (carbaryl and DDT) higher egg-totals than their untreated controls.
Abstract: A P-generation of female Tetranychus urticae Koch kept on residues of a 200 ppm spray of carbaryl, 100 ppm DDT, and 25 ppm dioxacarb showed significantly (carbaryl and DDT) higher egg-totals than their untreated controls. With dioxacarb the increase of egg production was marginal in the statistical analysis. The ratio females/males in the F1 was shifted in favor of the females in the broods reared on carbaryl and DDT residues, but not in the case of dioxacarb. This increase in the female proportion is highly significant for carbaryl with the strongest shift and DDT with a lesser one. Adult females of the F1, too, had a significantly higher egg production on carbaryl and DDT than their untreated counterparts. Hormoligosis—stimulation by small quantities of a stressor—is assumed responsible for observed effects, not an improved nutritional basis via an altered physiology of the host plant.
83 citations
TL;DR: In areas with high lead emission from the exhaust of vehicles, insects contained averages of 10.3, 15.5, and 25.0 ppm lead (oven dry weight) for species that suck plant juices, chew plant parts, and prey on other insects respectively, indicating a biological concentration of lead from herbivore to carnivore trophic levels.
Abstract: In areas with high lead emission from the exhaust of vehicles, insects contained averages of 10.3, 15.5, and 25.0 ppm lead (oven dry weight) for species that suck plant juices, chew plant parts, and prey on other insects respectively, indicating a biological concentration of lead from herbivore to carnivore trophic levels. In low lead emission areas insects in the same feeding categories had average lead contents of 4.7, 3.4, and 3.3 ppm respectively and showed no significant differences.
72 citations
TL;DR: The 3 methods were equally effective in sampling adults of geocorids and nabids and Larvae of P. scabra were sampled more effectively by the sweep-net method, and D-Vac samples consistently gave very low population estimates of all lepidopterous species.
Abstract: Sweep-net, D-Vac®, and ground-cloth sampling methods were compared by taking weekly samples of insect pests and beneficial arthropods associated with soybeans from Aug, 2–Sept. 26, 1972. Sample means were derived from 20 samples from each of 3 one-acre soybean fields.
Generally with all 3 sampling procedures, samples having low mean numbers yielded higher coefficients of variability. Linear regression of coefficients of variability on the sample means revealed high correlations, and analysis of covariance on weighted means revealed no significant difference among D-Vac, sweep, and ground-cloth sample methods.
The ground-cloth method produced higher means for most of the species collected in this study (spiders, Geocoris spp. nymphs, Nabis spp. nymphs, large larvae of Plathypena scabra (F.), and larvae of Heliothis spp., Trichoplusia ni (Hubner), Pseudoplusia includens (Walker), and Epilachna varivestis Mulsant. The 3 methods were equally effective in sampling adults of geocorids and nabids. Larvae of P. scabra were sampled more effectively by the sweep-net method. D-Vac samples consistently gave very low population estimates of all lepidopterous species.
70 citations
TL;DR: This model combines 2 equations, one expressing survival as a direct function of attack density, and the other survival as an inverse function of density, to describe the components of productivity in bark beetle populations.
Abstract: The components of productivity (offspring produced per parent) in bark beetle populations are defined as multiplication and survival. Data from the literature are used to formulate simple models relating these components to initial density in infested trees. A simple monotonic exponential decay function is proposed for describing the multiplication component, although data for validation are scarce. A humpbacked function is proposed for the survival component. This model combines 2 equations, one expressing survival as a direct function of attack density, and the other survival as an inverse function of density.
68 citations
TL;DR: The responsiveness of the P. pseudopallipes females was shown to be related to the number of eggs in their ovaries, and the flowers of Erigeron were also preferred for feeding, and this feeding apparently was necessary for maximum longevity.
Abstract: The olfactory responses of Peristenus pseudopallipes (Loan) to the odors of some food plants of its host, the tarnished plant bug ( Lygus lineolaris Palisot deBeauvois), were studied. The parasitoid females responded preferentially to Erigeron plant odor in a Y-tube olfactometer. The attractive odor was shown to emanate from the flowers. The responsiveness of the P. pseudopallipes females was shown to be related to the number of eggs in their ovaries. The flowers of Erigeron were also preferred for feeding, and this feeding apparently was necessary for maximum longevity.
67 citations
TL;DR: A model is described for stimulation of the population dynamics of Heliothis spp.
Abstract: A model is described for stimulation of the population dynamics of Heliothis spp. The salient features of the model include: (1) developmental means and variances about these means nonlinearly dependent on temperature; (2) separation of the general adult pool through adult attraction to spatially and temporally variant host-plant characteristics; and (3) cannabalism as a function of larval density, age-class structure within larvae, available feeding sites, and larval spatial distribution.
Results of an initial simulation effort are also presented.
65 citations
TL;DR: The Heliothis nuclear polyhedrosis virus was rapidly inactivated under field conditions on the upper leaf surface of cotton, soybean, and tomato and persistence on tomato was significantly better than on the other hosts.
Abstract: The Heliothis nuclear polyhedrosis virus was rapidly inactivated under field conditions on the upper leaf surface of cotton, soybean, and tomato. Inactivation of the virus was most rapid on cotton with little activity remaining after 24 h. While persistence on tomato was significantly better than on the other hosts, little virus activity remained after 96 h. Use of Shade™ and lignin sulfate as ultraviolet screens resulted in good virus persistence on all hosts through 48 h. Caging plants at night to prevent dew formation did not reduce virus inactivation. Persistence was good when plants were exposed from dusk to dawn but caged during the day to prevent sunlight inactivation. Undcr these conditions inactivation was greatest on cotton with 57% virus activity remaining after 96 h. Continuously caged plants of all hosts also had some loss of activity and while generally less than on plants exposed from dusk to dawn was not significantly different.
62 citations
TL;DR: Mineral accumulation associated with western harvester ant colonies represents a nutrient pool in a localized area—an important consideration when evaluating mineral cycling in the shortgrass ecosystem.
Abstract: The activities of Pogonomyrmex occidentalis (Cresson) result in alterations to the shortgrass plains ecosystem of northeastern Colorado. During nest construction and maintenance, large amounts of soil (2.8 kg/colony) are transferred to the surface and certain soil characteristics modified. Bulk density is lower beneath the mound, and sand content of the nest area higher in comparison to that of the surrounding area.
The plant-clearing habits of these ants exert only a minor influence on total plant cover. The maximum area cleared (27.3 m2/ha) occurred in an ungrazed area, which represents 0.3% of the total area. There was an increase in vegetation standing crop values around the cleared disc which partially compensates for the clearings. Higher P and NO3 concentrations were detected in the vicinity of the mound. Mineral accumulation associated with western harvester ant colonies represents a nutrient pool in a localized area—an important consideration when evaluating mineral cycling in the shortgrass ecosystem.
61 citations
TL;DR: The side effects of candidate mosquito control agents against nontarget organisms were investigated in the laboratory and outdoors in artificial containers, intermittent ponds, and irrigated pastures and adult emergence of mayflies and aquatic midges was affected by TH 6040 treatments.
Abstract: The side effects of candidate mosquito control agents against nontarget organisms were investigated in the laboratory and outdoors in artificial containers, intermittent ponds, and irrigated pastures. The compounds used were TH 6040 [1-(4-chlorophenyl)- 3-(2, 6-difluorobenzoyl)-urea], H 24108 [3-butyn-2 yl N - ( p -chlorophenyl) carbamate], and Altosid® [isopropyl 11-methoxy-3, 7, 11-trimethyl-2, 4 dodecadienoate].
In the laboratory, crustaceans, especially the tadpole shrimp, Triops longicaudatus LeConte, clam shrimp, Eulimnadia spp., and water fleas, Daphnia and Moina spp., were susceptible to TH 6040 at levels below 0.01 ppm. Copepods, Cyclops and Diaptomus spp., showed some tolerance at 0.01 ppm, whereas seed shrimp, Cypricerus and Cypridopsis spp., were tolerant to as much as 0.5 ppm. Among aquatic insects tested, mayfly nymphs, Callibaetis spp., and chironomid midge larvae, Goeldichironomus holoprasinus (Goeldi), were sensitive. However, beetles, Thermonectus basillaris (Harris), Laccophilus spp., Hydrophilus triangularis Say, and Tropisternus lateralis (F.), demonstrated a strong tolerance. Mosquitofish, Gambusia affinis (Baird and Girard), also showed no effect at high dose levels.
In artificial containers, TH 6040 suppressed the cladocera and copepod populations, but they recovered again. There was no effect on seed shrimp and the sideswimmer, Hyalella azteca (Saussure). TH 6040 also suppressed reproduction of the backswimmer, Notonecta unifasciata Guerin. There was no adverse effect on the backswimmer and mosquitofish colonies when the SR-1O formulation of Altosid was applied.
In field tests, TH 6040 suppressed populations of tadpole shrimp, clam shrimp, water fleas, and copepods; but these recovered soon. Adult emergence of mayflies and aquatic midges was affected by TH 6040 treatments. Some affected midge pupae were noticed when Altosid was applied.
TL;DR: Emergence of alate Solenopsis invicta Buren from several habitats in northern Florida averaged 187,000/acre/year, and first flights composed of alates which developed from the new season's brood occurred in late April and early May.
Abstract: Emergence of alate Solenopsis invicta Buren from several habitats in northern Florida averaged 187,000/acre/year The number of active mounds per acre varied between habitats, and the numbers of alates produced was not directly correlated with the numbers of mounds per acre Alates were captured each month, with the heaviest flights occurring April through August Of the alates captured, 52% were females Some habitats produced a higher male:female sex ratio than others About 90% of the flights were composed of over 74% of one sex of alates; 65% of the flights were monosexual Rainfall stimulated flights, but high relative humidity did not Some flights continued for 2–3 days after a rain Colonies sometimes had more than one mound, and flight could occur from either or both mounds Artificially created air movement terminated flights, but shading did not Two ovipositing queens were found in a single colony Sexual brood appeared in mounds in March, and first flights composed of alates which developed from the new season's brood occurred in late April and early May Dealate and deformed sexual forms which had been carried over the winter were seen attempting to fly in the spring
TL;DR: A compound released by females of Plodia interpunctella inhibits the responses of male Cadra cautella to the sex pheromone ( Z,E )-9,12-tetradecadien-1-ol acetate.
Abstract: A compound released by females of Plodia interpunctella (Hubner) inhibits the responses of male Cadra cautella (Walker) to the sex pheromone ( Z,E )-9,12-tetradecadien-1-ol acetate. The material was isolated and identified as ( Z,E )-9,12-tetradecadien-1-ol.
TL;DR: Adult Pieris rapae (L.) collected from a collard field that had been treated with an aqueous solution of rubidium chloride were found to contain levels of Rb significantly above the levels of those collected near untreated vegetables, using ordinary rubidium as a tag for native phytophagous insects.
Abstract: Adult Pieris rapae (L.) collected from a collard field that had been treated with an aqueous solution of rubidium chloride were found to contain levels of Rb significantly above the levels of those collected near untreated vegetables. Ordinary rubidium can therefore be used as a tag for native phytophagous insects.
TL;DR: For example, this article found that laboratory-reared females show no diel periodicity in pheromone emission, and release very small amounts of pherome (4.9 ng/30 min).
Abstract: Wild female Porthetria dispar adults emitted attractant at any time of day but made a maximal release between 1000–1530 h. Pheromone emission is greatest during the first 3 days of a virgin female's adult life and after the 3rd day decreases until death. Wild females emit a burst of pheromone, as much as 841 ng/30 min, once in their life, usually on the 2nd or 3rd day. After the burst the amount of lure emitted decreases rapidly. Unlike wild females, laboratory-reared (lab) females show no diel periodicity in pheromone emission, and release very small amounts of pheromone (4.9 ng/30 min).
Laboratory and field bioassays indicated that approximately 30% of both sexes of lab moths either did not respond to pheromone or released no detectable amount of lure, compared with 9% sexual inactivity in wild moths.
TL;DR: In this article, the impact of grasshoppers on rangeland forage production, especially during years of high population levels, has been well documented by previous authors (Pfadt 1949, Nerney 1960, Putnam 1962).
Abstract: The impact of grasshoppers on rangeland forage production, especially during years of high population levels, has been well documented by previous authors (Pfadt 1949, Nerney 1960, Putnam 1962). Most of this work, however, has concerned itself with measuring reductions in yield of various herbage species and/or grassland communities. With the recent surge of the concept of the ecosystem and its resultant impact upon ecological research (Watt 1966, Van Dyne 1969), it has become increasingly essential for research workers to adopt more holocoenotic approaches to the analyses of these relationships. Such is especially the case if the role of insects in ecosystem function is to be investigated.
This study has taken unpublished data and examined them in the context of determining what is the most “important” ecological effect that grasshoppers have on the structure and function of a shortgrass prairie eco-system
TL;DR: In a densely populated pasture near Hammond, La., Solenopsis Invicta Buren mounds have an aggregate distribution with an average mound density of 0.0096/m, and Monomorium workers appeared to possess a powerful poison which, when spread in the air, had a strong repellent effect against S. invicta workers.
Abstract: In a densely populated pasture near Hammond, La., Solenopsis invicta Buren mounds have an aggregate distribution with an average mound density of 0.0096/m. Only 2 other ant species, Monomorium minimum (Buckley) and Paratrechina arenivaga (Wheeler), were common. A native fire ant, S. xyloni McCook, occurred in the soil under several large trees.
Random distribution of baits in the field showed that, during daytime, 92–96% of the baits was first discovered by S. invicta , but 100% of them was exploited by this species. On the other hand, only 70% of the baits distributed on the S. invicta mounds was exploited by S. invicta itself, while the remaining 30% was exploited mainly by M. minimum. Monomorium workers appeared to possess a powerful poison which, when spread in the air, had a strong repellent effect against S. invicta workers. In this way Monomorium was often successful even in direct competition for food with S. invicta . This aggression-defense mechanism seemed to be ineffective against the native fire ant, S. xyloni , although the behavior of Monomorium to both species of fire ants appeared to be exactly the same and the responses of both species of fire ants seemed identical.
TL;DR: Daily rhythm and age at appearance of attraction in this species coincides with mating, which indicates that these 2 functions are associated, and sexual attraction seems to be regulated by light intensity and reaches maximum levels during the last hour of the photophase.
Abstract: Sexual attraction was observed in Dacus oleae (Gmelin) which, as opposed to all other tephritid fruit flies examined, is generated by the females and is directed exclusively toward the males. It is conjectured that in this sexual attraction an airborne pheromone is involved. Daily rhythm and age at appearance of attraction in this species coincides with mating, which indicates that these 2 functions are associated. Sexual attraction seems to be regulated by light intensity and reaches maximum levels during the last hour of the photophase. Females start attracting males from the 2nd day of post-emergence life, while males respond to female attraction after the 3rd day of their adult life. In flies of the same age, sexual attraction begins after the 3rd day of their adult life, reaches maximum at the age of 7–11 days, and starts decreasing from the 17th day. Mated females lose their attractiveness for a period of at least 6 days.
TL;DR: Dodecyl acetate inhibited attractancy of both Grapholitha species, and rubber septa containing 200 μg of the attractant mixture were the most attractive for G. molesta and this could be synergized with 600 μg of dodecyl alcohol.
Abstract: Optimum male Grapholitha molesta (Busck) attractancy to cis -8-dodecenyl acetate (c8–12:Ac) required 6–7% trans isomer, whereas male Grapholitha prunivora (Walsh) attractancy to c8–12:Ac was best when 2.2% of the trans isomer was present. Rubber septa containing 200 μg of the attractant mixture (6.6% trans) were the most attractive for G. molesta and this could be synergized with 600 μg of dodecyl alcohol. Dodecyl acetate inhibited attractancy of both Grapholitha species.
TL;DR: Responses to color glass filters placed over various white or metallic surfaces indicated a high preference of F. tritici for surfaces which remit only the near UV, the visible spectrum above 500 nm or which have a strong peak remission in the blue-violet region.
Abstract: The color preferences of 3 thrips populations were determined by placing 7.5×12.7-cm painted cards coated with Stickem® on 1.3 m stakes in a rye field. Sericothrips variabilis Beach was most attracted to yellow, Anaphothrips obscurus Muller and Frankliniella fusca (Hinds) to yellow and white, and F. tritici (Fitch) to yellow and low ultraviolet remitting white surfaces. In the greenhouse, the thrips Taeniothrips simplex (Morison) was most attracted to orange. Only F. tritici , a general flower inhabitant, clearly distinguished between low and high UV remitting white surfaces. Dilutions of paints with zinc white (a low UV remitter) revealed a consistent linear relationship between the catch of F. tritici and the percentage zinc white in the mixtures within the upper and lower limits of response. In a black-zinc white dilution series, the catch of F. tritici increased at a near linear rate with the logarithm of the increase in the mean percent remission from 400 to 660 nm. Dilutions of red or black with lead white (a high UV remitter) produced no distinctive responses; however, certain dilutions of yellow with lead white caught more F. tritici than the corresponding zinc white dilutions. Responses to color glass filters placed over various white or metallic surfaces indicated a high preference of F. tritici for surfaces which remit only the near UV, the visible spectrum above 500 nm or which have a strong peak remission in the blue-violet region. It was also confirmed that elimination of the near UV remission by lead white and by aluminum foil increased their attractiveness to the level of zinc white.
Lead white borders (28 cm2) greatly reduced the catch of all thrips species on 7 cm2 yellow center cards, and a white paper border greatly reduced the catch of F. tritici on all 5 colors tested.
TL;DR: It is concluded that the inhibitor is most probably perceived via a sensory neuron separate from that for the pheromone and modification of the phersomone response occurs via a more central integrative process.
Abstract: Z -7-dodecen-1-ol prevents males of Trichoplusia ni (Hubner) and Pseudoplusia includens (Walker) from orienting to a locus of the evaporating sex pheromone, Z -7-dodecen-1-ol acetate. Pheromone perception is not blocked by the inhibitor in that males exhibit excited upwind flight and clasper extension when exposed to pheromone plus inhibitor and preexposure to the inhibitor does not cause fatigue (habituation) of the male pheromone response. We conclude that the inhibitor is most probably perceived via a sensory neuron separate from that for the pheromone and modification of the pheromone response occurs via a more central integrative process.
TL;DR: The half-life of spores and endocrystals of Bacillus thuringiensis Berliner on soybean leaves was less than 24 h, since 65% of the insecticidal activity, and 90%" of the spore viability, was lost during the 1st day.
Abstract: The half-life of spores and endocrystals of Bacillus thuringiensis Berliner on soybean leaves was less than 24 h, since 65% of the insecticidal activity, and 90% of the spore viability, was lost during the 1st day. However, some insecticidal activity could be detected at 7 days postapplication. The half-life of the nucleopolyhedrosis virus of Heliothis ( Baculovirus heliothis ) was >2 <3 days. Viral activity could not be detected after 14 days' exposure on soybean leaves.
TL;DR: Individual releases of Trichogramma adults per acre on up to 48 acres of cotton at College Station, Tex., resulted in parasitism of Heliothis eggs averaging from 33–81%, with some movement of parasites up to 400 ft within 2 days.
Abstract: Individual releases of 19,000–387,500 Trichogramma adults per acre on up to 48 acres of cotton at College Station, Tex., resulted in parasitism of Heliothis eggs averaging from 33–81%, with some movement of parasites up to 400 ft within 2 days.
Subsequent generations of Trichogramma were not produced in the field due to mortality, apparently caused by drift of methyl parathion (ultra-low volume) which killed 75% of the adult Trichogramma at distances of up to one mile downwind from sprayed fields.
TL;DR: Activity times of Pogonomyrmex occidentalis (Cresson) were found to vary with soil surface temperatures, and studies conducted on populations in lightly- and heavily-grazed pastures showed no significant differences in the rate of foraging extraction, foraging distance, time per foraging trip, or availability of forage (seeds).
Abstract: Activity times of Pogonomyrmex occidentalis (Cresson) were found to vary with soil surface temperatures. Polynomial equations describe the relationship between the number of foraging ants leaving the colony and surface temperatures.
Thirty-nine percent of forage particles brought into the colony were seeds and 24% were litter. The remainder consisted of dead insect material, insect prey, fecal matter, and rocks being brought in for mound construction.
Studies conducted on populations in lightly- and heavily-grazed pastures showed no significant differences in the rate of forage extraction, foraging distance, time per foraging trip, or availability of forage (seeds). The ants removed about 2% of the seed biomass available to them.
TL;DR: Data from the first year of disruption shows for both species there was almost total disruption of male orientation to attractant and live female traps, and that there was a substantial reduction in crop damage.
Abstract: Mass trapping for redbanded leafroller (RBLR), Argyrotaenia velutinana , and grape berry moth, Paralobesia viteana , in 2 vineyards in 1971 resulted in a substantial reduction in percent of damage compared to a check area. An extremely high population of RBLR was present, but located mainly outside the vineyard. In 1972 mass trapping experiments were continued in one vineyard, with results similar to 1971, and a mating disruption experiment initiated in the other vineyard. Data from the first year of disruption shows for both species there was almost total disruption of male orientation to attractant and live female traps, and that there was a substantial reduction in crop damage. The close proximity (12.2 m) of high populations in the check vineyard could have influenced damage counts in the disruption experiment.
TL;DR: The response of the parasitoid in an olfactometer to a host insect (greenbug), a non-host insect ( Heliothis zea], an aphid host plant (sorghum), and a plant on which aphids seldom colonize is studied.
Abstract: Lysiphlebus testaceipes (Cresson) is the most abundant parasitoid of the greenbug, Schizaphis graminum (Rondani) and helps to limit infestations (Jackson et al. 1970) but often not until damage to grain sorghum has occurred. Several authors have noted different preferences of L. testaceipes for aphid hosts on different host plants (Knight 1944, Sekhar 1960, Walker et a1. 1973). We studied the response of the parasitoid in an olfactometer to a host insect (greenbug), a non-host insect ( Heliothis zea [Boddie]), an aphid host plant (sorghum), and a plant on which aphids seldom colonize (peanut cactus, Chamaecereus silvestrii [Speg.]).
TL;DR: Host preference tests were conducted on Lygus hesperus Knight and L. elisus Van Duzee in cotton fields interplanted with 20-ft wide strips of alfalfa at 130- to 540-ft intervals and in various patterns of al falfa row spacing to demonstrate the efficiency of using alfalinga as a trap crop for lygus bugs in cotton.
Abstract: Host preference tests were conducted on Lygus hesperus Knight and L. elisus Van Duzee in cotton fields interplanted with 20-ft wide strips of alfalfa at 130- to 540-ft intervals and in various patterns of alfalfa row spacing. The distinct preference of lygus bugs for alfalfa over cotton was significantly demonstrated even when samples were taken in the 2 crops 3 ft apart. These studies demonstrate the efficiency of using alfalfa as a trap crop for lygus bugs in cotton.
TL;DR: A diverse assemblage of phytophagous insects representing 7 orders, 23 families, and more than 40 species fed or reproduced on Italian thistle, Carduus pycnocephalus L. (Compositae) in southern California, showed signs of attacking this introduced annual weed, where this thistle was relatively free of deleterious insect injury.
Abstract: A diverse assemblage of phytophagous insects representing 7 orders, 23 families, and more than 40 species fed or reproduced on Italian thistle, Carduus pycnocephalus L. (Compositae) in southern California. Most of the insects attacking this introduced annual weed were euryphagous, ectophagous, sap- and foliage-feeding species. Half of the identified insect associates were economic species.
In southern Europe, Italian thistle hosts a far greater diversity of phytophagous insects; those detected to date represent 8 orders, 31 families, and more than 80 species. All major plant parts are damaged by one or more species of insects, unlike the situation in southern California, where this thistle was relatively free of deleterious insect injury. About a third of the European insect associates of Italian thistle were endophagous as immatures. A third of the associates identified to species were stenophagous, restricted to host-plants belonging to the tribe Cynareae.
Only 3 species (ca. 4%) of the insect enemies of Italian thistle in Europe immediately appeared promising for use as biological control agents in southern California: Psylliodes chalcomera Illiger (Coleoptera: Chrysomelidae), Ceutorhynchus trimaculatus F. (Coleoptera: Curculionidae), and Rhinocyllus conicus Froelich (Coleoptera: Curculionidae). The last-named, seed-destroying species was initially colonized on Italian thistle in southern California in 1973.
TL;DR: Aroclor 1254 was the most active inhibitor of growth and photosynthesis in C. pyrenoidosa .
Abstract: The effects of DDT, dieldrin, carbaryl, parathion, piperonyl butoxide and Aroclor 1254®, a polychlorinated biphenyl containing 54% chlorine, on growth and photo-synthesis in the freshwater alga Chlorella pyrenoidosa Chick were measured. Inhibition was most easily demonstrated by varying the concentratIon of the alga and keeping the chemical concentration constant. Aroclor 1254 was the most active inhibitor of growth and photosynthesis in C. pyrenoidosa . Piperonyl butoxide, an insecticide synergist, and parathion were also strong inhibitors of growth and photosynthesis while DDT was less active. Dieldrin and carbaryl were least potent as inhibitors.
TL;DR: In this article, the authors conducted laboratory and field studies on the longevity, fecundity, and searching ability of Trichogramma reared on two hosts and stored at reduced temperatures.
Abstract: Previous research with different species of Trichogramma has indicated that the size or species of the host egg in which the parasite develops may alter its efficiency (Salt 1940, Marston and Ertle 1973). Also, storing of Trichogramma pupae at reduced temperatures weakens the emerging parasites (Schread and Garman1934). Since the host used to rear Trichogramma may greatly affect the rearing costs, and since cold storage of pupae may ease handling of the parasites for field use(Stinner and Ridgway, unpublished data), information was needed about the effects of these factors on Trichogramma . Therefore, we conducted laboratory and field studies on the longevity, fecundity, and searching ability of Trichogramma reared on 2 hosts and stored at reduced temperatures.