Biological control of the fruit‐spotting bug Amblypelta lutescens using weaver ants Oecophylla smaragdina on African mahoganies in Australia

• 1 African mahogany Khaya senegalensis is a high‐value timber tree. Pilot plantings showed that the fruit‐spotting bug Amblypelta lutescens causes severe damage of the tree in the wet–dry tropics of northern Australia. The weaver ant Oecophylla smaragdina is an efficient biocontrol agent in some horticulture crops. To investigate whether the ants control this pest, field experiments were conducted from April 2006 to January 2009 at two study sites in the Darwin area, Australia. A laboratory experiment was carried out in March 2007 at Berrimah Farm.
• 2 During the experimental period, in the weaver ant treatments, the overall percentage of trees damaged by the pest was 0–8% at both sites, and the damaged trees were attacked once only. In the treatments without weaver ants, however, the damage level was > 80% at Berrimah Farm and 31–100% at Howard Springs, and the damaged trees were attacked more than once.
• 3 The mean percentage of trees damaged per monitoring occasion was 0–2.6% in the weaver ant treatments at both sites, whereas, in the treatments without the ants, the damage percentages were 14.2–27.0% at Howard Springs and 28.2–48.6% at Berrimah Farm.
• 4 Extrafloral nectar of African mahoganies is attractive to weaver ants. Fruit‐spotting bugs only damage the tender parts of flushing shoots and growing tips. Weaver ants live on sugar solution and meat, and they frequently harvest extrafloral nectar on growing shoots, on which they catch nymphs of the pest for their meat supply. The aggressive behaviour of the ants also repels the pest away from flushing shoots.
• 5 The data suggest that weaver ants were effective biocontrol agents of fruit‐spotting bugs, and the ants can be used to manage the pest on African mahoganies.
• 6 The present study demonstrates that the introduced African mahogany comprises another major host of the fruit‐spotting bug.

     

True bug (Heteroptera) impact on cocoa fruit mortality and productivity

The real impact of true bug damage on cocoa pods has never been assessed precisely. We conducted a 2-yr study on 1,080 cocoa trees on 36 farms in Cameroon to assess the contribution of true bugs to fruit mortality and production loss. The cocoa fruiting cycle, fruit mortality, and damage caused by true bugs as well as other pests and diseases were monitored on a weekly basis. True bug damage also was described on 2,500 ripe pods per year. Pod weight, bean number, and bean weight were measured and compared for different degrees and types of damage on the ripe pods. Our results showed that true bugs were the main external cause of young fruit abortion. They reduced the abundance of young fruit by up to 10%. In contrast, although one-third of the ripe pods sampled had true bug lesions, only 4% were moderately to heavily damaged. The mean weight of ripe pods was reduced by 12% when there was medium to heavy damage. While the mean weight of wet beans was reduced significantly (by 3-10%), the number of beans per pod was not changed by damage. Despite the reduction in mean weight, the overall weight of beans for the pods sampled was reduced by <2%. Therefore, our study confirmed the common assumption that the economic impact of true bug damage on mature pods is negligible on cocoa farms in Cameroon. However, true bugs have a significant impact on young fruit mortality.     

The influence of cypermethrin and oxydemeton-methyl treatment on Lygus damage in young Scots pine seedlings

Laboratory experiments were carried out to evaluate the efficiency of two insecticides, cypermethrin and oxydemeton-methyl, in controlling the nymphs and adults of Lygus bugs and the resulting damage caused by these bugs to small pine seedlings. Both insecticides significantly increased the mortality of bugs on the seedlings compared with bug mortality on untreated controls. Mortality of bugs was higher in the oxydemeton-methyl treatment than in the cypermethrin treatment. The occurrence of seedlings with multiple leaders and the number of leader shoots per seedling were significantly decreased in insecticide-treated seedlings. Mean number of leader shoots was significantly higher in seedlings treated with oxydemeton-methyl than in seedlings treated with cypermethrin after a 24-h exposure to nymphal instars of Lygus. The mortality of the pine seedlings was very low but significantly decreased in insecticidal treatments. Factors affecting the effects of different insecticides on bug mortality and their efficiency in controlling the multiple-leadering phenomenon are discussed.     

Feeding Activity, Salivary Amylase Activity, and Superficial Damage to Soybean Seed by Adult Edessa meditabunda (F.) and Euschistus heros (F.) (Hemiptera: Pentatomidae)

Greenhouse and laboratory studies were conducted to evaluate feeding activity and superficial damage to soybean seed by the brown-winged stink bug, Edessa meditabunda (F.), and the Neotropical brown stink bug, Euschistus heros (F.). Soybean plants (cv. BRS 282), at R6 stage of development were used. Thirty pairs of each species were used individually for 48?h. Two daily observations (9:00?AM and 3:00?PM) were taken to record the number of bugs (feeding/resting) on plant parts. Harvested seeds imbibed in tetrazolium solution were photographed for measurement of the damaged surface. Adult E. meditabunda significantly preferred soybean stems (19.7 bugs) to pods (2.7). Feeding/resting was similar at 9:00?AM (mean number of 28.0 bugs) and 3:00?PM (24.3). Euschistus heros equally fed/stayed on stems (7.3 bugs) and pods (6.9), although most bugs (12.3) remained on the cage net; feeding/resting on all plant structures amounted to 13.7 bugs at 9:00?AM and 17.7 bugs at 3:00?PM. Amylase activity was greater for E. heros (41.61?±?0.89?U/mg) and almost none for E. meditabunda (2.35?±?0.14?U/mg). The superficial damage to seeds was significantly greater for E. meditabunda (22. 9?mm²) compared to E. heros (12.5?mm²). However, E. meditabunda caused less shrinkage of the seed tegument, while E. heros damage was deeper and seeds showed reduction in size.     

Nesidiocoris tenuis as a pest in Northwest Europe: Intervention threshold and influence of Pepino mosaic virus

The use of Nesidiocoris tenuis (Hemiptera: Miridae) as a biocontrol agent is controversial as it is considered a pest in Northwest European tomato greenhouses, due to its tendency to damage the plant and fruit. Necessary chemical plant protection products to control N. tenuis have toxic side effects on important beneficials like Macrolophus pygmaeus (Hemiptera: Miridae), which jeopardizes the whole IPM programme. In this study, several commercial tomato greenhouses were monitored for mirid populations. The relationship between the number of N. tenuis individuals and plant damage was assessed in function of availability of prey and interaction with M. pygmaeus. These greenhouse data were used to determine a practical density intervention threshold. Next, the hypothesis that a Pepino mosaic virus (PepMV) infection increases plant and fruit damage by N. tenuis (as has been shown for M. pygmaeus) was tested. Plant damage occurred when the average number of predatory bugs in the head of the plant exceeded 16 per ten plants. Plant damage increased in severity at increasing predatory bug densities, independent of the availability of prey and M. pygmaeus presence. Plant and fruit damage were not affected by the presence of PepMV, as was shown for fruit damage in previous studies for M. pygmaeus. Our study provides a practical density intervention threshold for growers in greenhouse crops. Simple monitoring of the number of predatory bugs in the head of the plant can be used to take specific biocontrol actions. It was also shown that only the predatory bug N. tenuis itself causes damage, and there is no interaction with PepMV.     

Buffalograss germplasm resistance to Blissus occiduus (Hemiptera: Lygaeidae)

Plant germplasm collections may offer genetic variability useful in identifying insect resistance. The goal of this project was to evaluate buffalograss genotypes [Buchlo? dactyloides (Nutt.) Engelm.] for resistance to the chinch bug, Blissus occiduus Barber (Hemiptera: Lygaeidae), and to relate resistance to ploidy level, chinch bug number, and pubescence. Forty-eight buffalograss genotypes from diverse geographic locations were evaluated in replicated studies under greenhouse conditions. Of the genotypes studied, four were highly resistant, 22 were moderately resistant, 19 were moderately susceptible, and three were highly susceptible to chinch bug damage. The mean number of chinch bugs was significantly different among the 48 genotypes. There was no significant correlation between chinch bug resistance and ploidy level or chinch bug resistance and pubescence. These results indicate the genetic source of resistance to chinch bugs exists in buffalograss germplasm. Highly resistant genotypes can be used in breeding programs to further improve buffalograss cultivars.     

The impact of global warming and land-use change on the pest status of rice and fruit bugs (Heteroptera) in Japan

Infestation by rice and fruit bugs (Heteroptera) became a nationwide problem in Japan in the early 1970s. Nine rice bug species and three fruit bug species have been designated as economically important. Cropping restrictions for rice produced fallow paddy fields where various rice bugs reproduced and became abundant. Plautia crossota stali, Halyomorpha halys and Glaucias subpunctatus are dominant species of fruit bug that cause damage to a range of fruit crops. However, they require cones in order to complete their life cycle. Coniferous trees planted in the 1950s bore cones after 20 years. A dry and hot summer contributes to good masting the following year and good cone production, in turn, contributes to the abundance of fruit bugs in the third year. Thus, there is strong circumstantial evidence that land‐use changes were responsible for the abundance of both rice and fruit bugs during the last 30 years. Poleward range expansion was observed in Nezara viridula, Leptocorisa chinensis, G. subpunctatus and Paradasynus spinosus. A survey conducted to assess winter mortality revealed that every 1 °C rise in mean winter temperature resulted in a reduction of about 15% in winter mortality of N. viridula and H. halys in localities where the mean winter temperature ranges from 2 to 6 °C. In general, species with low developmental zero (T₀) and small thermal constant (K) show the greatest increase in annual number of generations. Species with a high T₀ for preoviposition period show the greatest increase in reproductive activity, while overwintering insects with a lower T₀ tend to appear earlier in response to the elevation of temperature. Numbers of warnings issued by the prefectures on the occurrence of rice bugs and fruit bugs were correlated. Recent global warming operates in various ways, (e.g. by increasing annual number of generations, reproductive activity and food, to produce such correlation). There are no substantial bug problems in Korea where no significant land‐use changes have occurred. Rice bug outbreaks in Japan are predicted to become less frequent in the future, because there is no further scope for cropping restriction. Planting of coniferous trees has been continuously decreasing since 1970, but the area of coniferous forest is still almost the same. This suggests that the fruit bug problem will continue for the foreseeable future.     

Tree diversity drives abundance and spatiotemporal β‐diversity of true bugs (Heteroptera)

1. Spatiotemporal patterns of canopy true bug diversity in forests of different tree species diversity have not yet been disentangled, although plant diversity has been shown to strongly impact the diversity and distribution of many insect communities. 2. Here we compare species richness of canopy true bugs across a tree diversity gradient ranging from simple beech to mixed forest stands. We analyse changes in community composition by additive partitioning of species diversity, for communities on various tree species, as well as for communities dwelling on beech alone. 3. Total species richness (γ‐diversity) and α‐diversity, and abundance of true bugs increased across the tree diversity gradient, while diversity changes were mediated by increased true bug abundance in the highly diverse forest stands. The same pattern was found for γ‐diversity in most functional guilds (e.g. forest specialists, herbivores, predators). Temporal and even more, spatial turnover (β‐diversity) among trees was closely related to tree diversity and accounted for ～90% of total γ‐diversity. 4. Results for beech alone were similar, but species turnover could not be related to the tree diversity gradient, and monthly turnover was higher compared to turnover among trees. 5. Our findings support the hypothesis that with increasing tree diversity and thereby increasing habitat heterogeneity, enhanced resource availability supports a greater number of individuals and species of true bugs. Tree species identity and the dissimilarity of true bug communities from tree to tree determine community patterns. 6. In conclusion, understanding diversity and distribution of insect communities in deciduous forests needs a perspective on patterns of spatiotemporal turnover. Heterogeneity among sites, tree species, as well as tree individuals contributed greatly to overall bug diversity.     

臭虫的再猖獗、生物学及防治研究进展

由于DDT等现代杀虫剂的问世,臭虫在20世纪40-50年代以后在全球大部分地区尤其是发达国家和地区销声匿迹,但近10多年来臭虫在部分国家和地区重新出现.本文对其再猖獗原因、生物学和行为、饲养、抗药性、监测与防治策略进行了综述,旨在引起国人的重视,对今后臭虫的监测和防治起到抛砖引玉的作用.本文分析了近15年有关温带臭虫Cimex lectulariusL.和热带臭虫C.hemipterus(F.)的研究文献.臭虫再猖獗被认为是因为它对目前使用的杀虫剂例如拟除虫菊酯类等产生抗性以及频繁的地区及国际交往等因素造成的.简单、经济和大规模臭虫种群饲养方法——人工膜饲喂法的研发为我们开展臭虫生物学和生态学研究提供了便利.控制和根除臭虫目前仍较困难,采用害虫综合治理(integrated pest management,IPM)策略,包括臭虫知识宣传、主动监测、非化学防治方法(例如:经常洗涤床上用品、蒸汽熏蒸、热处理、使用床垫罩、在家具腿下放置臭虫拦截装置)、有选择使用杀虫剂以及定期监测及反复防治等措施,可达到很好的防控效果.在我国部分地区,臭虫发生也呈上升趋势,工人宿舍和火车车厢是常见的臭虫为害环境.有必要对我国臭虫发生现状及其抗药性进行调查与监测.还应借鉴国际先进技术,研制出我国适用的、有效的监测工具和防治方法,并根据我国具体国情制定出切实可行的防治标准.同时积极开展臭虫科普宣传,做到早发现、早防治,防止臭虫再猖獗和扩散.     

Treatment thresholds for stink bugs (Hemiptera: Pentatomidae) in cotton

The green stink bug, Acrosternum hilare (Say), the southern green stink bug, Nezara viridula (L), and the brown stink bug, Euschistus servus (Say), were predominant phytophagous Pentatomidae detected during 1995-1997 in cotton in South Carolina. These species occurred in similar numbers in conventional and transgenic cotton 'NuCOTN33B', containing the gene for expression of CryIA(c) delta-endotoxin of Bacillus thuringiensis Berliner variety kurstaki. Adult stink bugs moved into cotton from wild and cultivated alternate hosts during July, and reproducing populations usually were detected in cotton from late July into September. Applications of either methyl parathion (0.56 kg [AI]/ha) directed for stink bugs or lambda-cyhalothrin (0.037 kg [AI]/ha) or cyfluthrin (0.056 kg [AI]/ha) for control of cotton bollworm, Helicoverpa zea (Boddie), provided effective control of pentatomids in NuCOTN33B or conventional 'DP5415' and increased yields compared with untreated plots. Fiber quality did not differ among treated or untreated plots of NuCOTN33B. The ground-cloth technique was used to estimate populations of stink bugs, and data indicated that treatment at one bug per 2 m of row adequately protected cotton from yield loss due to stink bug damage. Observations on boll damage indicated that treatment might be necessary if >20-25% reveal internal symptoms of feeding injury during mid- to late season. More detailed damage thresholds should be developed to complement an approach based on population monitoring. This study validated current recommendations for management of pentatomids in cotton, demonstrated the necessity of threshold use for stink bugs in transgenic cultivars expressing endotoxin from B. thuringiensis, and provided insight into further development of management options for pentatomids in the crop.     

The sex determination in Ellobius lutescens remains bizarre

Mammalian sex determination and gonad differentiation are the result of a complex interaction of fine-tuned spatial and temporal gene expression with threshold levels of individual genes. The male pathway is initiated by SRY. Some exceptional mammals determine male sex without the SRY gene and even without a Y chromosome. Ellobius lutescens in this report is one example of this "weird" species. We provide key data on the genomic level that there are no coarse differences in the genomes of male and female animals by comparative genomic hybridization. On the gene level we studied the gene Nr5a1 for the orphan nuclear receptor, steroidogenic factor SF-1, a central constituent for gonad differentiation and adrenal gland development. The Ellobius lutescens Nr5a1 gene was mapped to the proximal short arm of chromosome 2 by fluorescence in situ hybridization. In addition, we provide evidence by linkage analysis in two E. lutescens pedigrees that Nr5a1 is not the key male sex-determining gene in Ellobius lutescens.     

Soybean seed damage by different species of stink bugs

Abstract

• 1 Damage caused by the three main species of stink bugs occurring on soybean Nezara viridula (Linnaeus), Piezodorus guildinii (Westwood) and Euschistus heros (Fabricius) was compared in field cages and in greenhouses. Infestation levels of 4 stink bugs/m row of plants (field cages) and 2 stink bug/plant (greenhouse) for 15 days during the pod filling stage are reported. At harvest, the yield and seed quality were evaluated.
• 2 In the field, there was no difference in yield between infested and insect‐free plants, but damage to seed quality varied with stink bug species. Plants damaged by P. guildinii had the lowest quality seeds. From 50 g seed samples harvested in the field, the mean weight of seeds classified as ‘good’ was 37.3 g in plants infested with P. guildinii, compared to 41.8, 44.2 and 46.6 g in plants infested with E. heros, N. viridula and the control, respectively.
• 3 Plants infested with P. guildinii showed the highest number of seeds damaged by stink bugs, whereas those infested with E. heros showed the lowest damage.
• 4 Plants infested with P. guildinii had 18.5% damaged seeds, higher than the 3.6% and 3.4% damaged seeds from plants infested with the two other species and 0.1% in control plants. The percentage of non‐viable seeds due to stink bug damage was 5.7% for P. guildinii but lower for the other two species.

     

Interactions between panicle size, insect density, and environment for genotypic resistance in sorghum to head bug,Calocoris angustatus

Studies were undertaken on interactions between panicle size, insect density, host plant, and the environment for sorghum head bug,Calocoris angustatus Lethiery on five sorghum genotypes in terms of bug population increase, grain damage and loss in grain mass across four panicle sizes (5, 10 or 20 branches/panicle and whole panicle), and three infestation levels (5, 10 and 15 pairs of bugs/panicle). Head bug numbers increased and grain damage decreased with an increase in panicle size in the head bug susceptible cultivars, CSH 1 and CSH 5. However, the increase in bug numbers or decrease in grain damage was not significant in head bug resistant genotypes, IS 17610 and IS 17645. Head bug numbers increased with an increase in infestation level in CSH 1 and CSH 5, however, such an increase was not substantial in IS 17610 and IS 17645. Grain damage was significantly lower in IS 17610 and IS 17645 compared with CSH 1 and CSH 5 across infestation levels. Head bug population increased at a greater rate during the rainy season compared with the dry season. Panicle size and infestation levels accounted for greater variation in grain damage and percentage loss in grain mass during the rainy season than in the dry season. To identify reliable sources of resistance to insects, it is important to study insect host plant-interactions across panicle sizes (levels of food availability), infestation levels and seasons.     

Impact of Phyllocnistis citrella (Lepidoptera: Gracillariidae) on leaf area development and yield of mature citrus trees in the Mediterranean area

Seasonal population trends and damage to citrus trees by the leafminer Phyllocnistis citrella Stainton were studied in the Valencia area of eastern Spain from 1996 to 1999. The area-wide seasonal flushing pattern of citrus trees and leafminer population trends were determined in 10 mature citrus orchards. In the 10 orchards, the annual percentage of new shoots that developed in the spring ranged from 51 to 96% for individual orchards (mean of 80%). Phyllocnistis citrella populations damaged new leaves from July to November. During this period, approximately 45% of the new leaf area was lost due to leafminer mining. In addition, at three mature citrus orchards, two 'Navelina' sweet oranges from 1996 to 1999 and one 'Clementine' mandarin (variety 'Clemenules') in 1998 and 1999, the leaf area damage, spring flushing pattern, and crop yield were determined in trees sprayed one to three times a year with abamectin (Epimeck, 0.02%) to control P. citrella and compared with nonsprayed control trees. In these three orchards, damaged leaf area in summer-fall flushes was on average 52% in nonsprayed and 8% in sprayed trees. No significant differences were found between sprayed and nonsprayed trees in the spring flushing and flowering pattern, number of fruits or fruit diameter. In Mediterranean areas, P. citrella damaged only 5-15% of the annual new leaf area of mature trees and yield was usually not affected by the pest.     

Impact of reflective mulch on yield of strawberry plants and incidence of damage by tarnished plant bug (Heteroptera: Miridae).

The current study investigated the impact of reflective mulch on yield of strawberry plants and incidence of damage by tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), for three strawberry cultivars: 'Honeoye', 'Earliglow', and two sibling Dayneutrals ('Tribute' and 'Tristar', herein considered as one cultivar). Of all cultivars tested, Honeoye was the most productive and least susceptible to tarnished plant bug. For Earliglow and Honeoye, reflective mulch enhanced productivity of strawberry plants and suppressed density of nymphs per flower cluster and proportion of damaged fruits, but did not significantly impact numbers of nymphs or damaged fruits per hectare, Results with Dayneutrals were not consistently significant. Both in the presence or absence of reflective mulch, proportion of damaged fruits increased with increasing density of nymphs per flower cluster and with decreasing number of fruits harvested per row section, suggesting that planting productive strawberry cultivars or maintaining cultural practices that promote high yield may provide an effective line of defense against tarnished plant bug. These results also suggest that reflective mulch may suppress incidence of damage by tarnished plant bug both directly, by reducing number of nymphs per flower cluster, and indirectly, by enhancing productivity of strawberry plants. Economic analyses evaluating costs and benefits of using reflective mulch, as well as studies investigating mechanisms that underlie the impact of reflective mulch on yield and incidence of damage by tarnished plant bug, are still needed before reflective mulch can be implemented as a management strategy in commercial strawberry fields.     

Effectiveness of bed bug monitors for detecting and trapping bed bugs in apartments

Bed bugs, Cimex lectularius L., are now considered a serious urban pest in the United States. Because they are small and difficult to find, there has been strong interest in developing and using monitoring tools to detect bed bugs and evaluate the results of bed bug control efforts. Several bed bug monitoring devices were developed recently, but their effectiveness is unknown. We comparatively evaluated three active monitors that contain attractants: CDC3000, NightWatch, and a home-made dry ice trap. The Climbup Insect Interceptor, a passive monitor (without attractants), was used for estimating the bed bug numbers before and after placing active monitors. The results of the Interceptors also were compared with the results of the active monitors. In occupied apartments, the relative effectiveness of the active monitors was: dry ice trap > CDC3000 > NightWatch. In lightly infested apartments, the Interceptor (operated for 7 d) trapped similar number of bed bugs as the dry ice trap (operated for 1 d) and trapped more bed bugs than CDC3000 and NightWatch (operated for 1 d). The Interceptor was also more effective than visual inspections in detecting the presence of small numbers of bed bugs. CDC3000 and the dry ice trap operated for 1 d were equally as effective as the visual inspections for detecting very low level of infestations, whereas 1-d deployment of NightWatch detected significantly lower number of infestations compared with visual inspections. NightWatch was designed to be able to operate for several consecutive nights. When operated for four nights, NightWatch trapped similar number of bed bugs as the Interceptors operated for 10 d after deployment of NightWatch. We conclude these monitors are effective tools in detecting early bed bug infestations and evaluating the results of bed bug control programs.     

Comparison of management strategies for squash bugs (Hemiptera: Coreidae) in watermelon

Two watermelon pest management practices, a squash trap crop and a standard recommendation using soil-applied carbofuran, were compared using large-scale field plots to assess trap crop suitability as a replacement for the standard in 2000, 2001, and 2002. In both systems, foliar insecticide applications were used to control squash bugs when populations exceeded threshold levels. During 2001 and 2002, a treatment of untreated watermelon was used. Early season adult insects, from seedling to fruit set, are most critical for watermelon. Significantly fewer early adult bugs were found on watermelon in the trap crop than in the standard recommended practice in 1 of 3 yr. In both years, significantly fewer adult squash bugs were found in watermelon in the trap crop than in untreated fields. The standard recommended practice significantly reduced adult squash bugs in watermelon compared with the untreated in 1 of 2 yr. There was no significant correlation of watermelon yield and squash bug density, indicating that squash bug densities were too low to impact yield. Although squash bugs were reduced significantly by the trap crop, marketable watermelon yields were lower in the squash trap crop than in untreated watermelon, suggesting that pest management treatments may interfere with crop productivity factors other than squash bug colonization. Results suggest that mid-season production squash bug should be managed by monitoring populations and using insecticides as needed rather than using at-plant treatment. Further research is needed to compare treatments during early-season production.     

The potential of a jumping spider, Phidippus clarus, as a biocontrol agent

Spiders, particularly assemblages of species, have been shown to be effective in reducing pest insects and crop damage in field crops and orchards. We investigated the potential for a single jumping spider species to reduce pests in a greenhouse setting. We placed three treatments in large enclosures: 1) control treatment of only sweet basil, Ocimum basilicum L.; 2) sweet basil and a phytophagous pest, fourlined plant bug, Poecilocapsus lineatus (F.) (Heteroptera: Miridae); and 3) sweet basil, fourlined plant bug, and jumping spider Phidippus clarus (Keyserling 1884). After 1 wk, jumping spiders reduced the number of plant bugs. Plants exposed to plant bugs alone were significantly shorter than either control plants or plants exposed to plant bugs and spiders. Chlorophyll concentration did not significantly differ across treatments. We discuss the feasibility of using P. clarus and similar salticids in biocontrol.     

Evaluation of damage to physic nut (Jatropha curcas) by true bugs

The type of injury and amount of damage to the fruits and seeds of physic nut (Jatropha curcas L., Euphorbiaceae) caused by two species of fruit feeding true bugs, Pachycoris klugii Burmeister (Heteroptera: Scutelleridae) and Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae), and the flower feeding true bug, Hypselonotus intermedius Distant (Heteroptera: Coreidae), were assessed using field cages. The parameters analysed were infructescence, fruit, seed and seed kernel weight, seed length, fruit and seed abortion, seed malformation and oil and protein content of the seed kernels. All three species reduced overall yield. The two members of the fruit feeding guild led to premature fruit abortion and malformed seeds. Reduction of fruit, seed and seed kernel weight as well as seed length could be expressed as linear regressions of adult population densities. The oil content of the seeds was slightly reduced by the bugs, but protein content remained unchanged. Damage increased with the developmental stage of the larvae. Whereas adult L. zonatus of both sexes produced more damage than the nymphs, female P. klugii caused less damage than nymphs, and male P. klugii no significant damage at all. H. intermedius is a pollinator of this entomogamous plant. At high densities, however, it reduced the number of fruits maturing.     

Hairy chinch bug (Hemiptera: Lygaeidae) damage, population density, and movement in relation to the incidence of perennial ryegrass infected by Neotyphodium endophytes

Studies examined hairy chinch bug, Blissus leucopterus hirtus Montandon, damage, population density, and movement in stands of perennial ryegrass, Lolium perenne L., containing various proportions of endophyte infected plants (E+). Our main objective was to determine the utility of mixtures containing E+ for management of chinch bugs. Chinch bug damage and population density decreased linearly as the proportion of E+ increased. This trend held true even when chinch bug populations were extremely high. Chinch bug nymphs emigrated more quickly from stands containing 100% E+ than they did from stands containing 50 or 0% E+, whereas adult chinch bug emigration was relatively unaffected by the proportion of E+. Our results indicate that turfgrass mixtures containing E+ can reduce chinch bug damage and population density.