Pheromone trap catches as a means of predicting damage by pink bollworm larvae in cotton

The male moth catches in gossyplure-baited traps were used to predict larval infestation of pink bollworm, Pectinophora gossypiella (Saunders), in cotton fields during 1988 and 1989. The mean moth catches per trap per night were positively correlated with percentage larval infestation. The moth counts in traps and larval infestation in green bolls increased with advance in reproductive stage of the cotton plants. A mean trap catch of 9–12 pink bollworm moths per night was associated with economically damaging infestation. It is, therefore, inferred that insecticidal sprays may be scheduled when 9–12 moths are captured per trap per night.     

Optimization of a monitoring system for the pine beauty moth, Panolis flammea (Denis & Schiffermüller), using sex attractants

The efficiency of traps baited with synthetic sex attractants, (Z)-9- and (Z)-11-tetradecenyl acetates, for Panolis flammea (Denis & Schiffermüller) (Lepidoptera: Noctuidae) was tested with respect to trap design, capacity, height, alignment, position and dose of lure. For optimum catches, traps should not be obstructed by vegetation, and can be placed most conveniently in forest rides. The most important features of trap design were a heavy surface coating of sticky retentive material and a large catching area. The efficiency of capture decreased rapidly when 40 or more moths were present on a sticky surface of area 380 cm². Numbers of moths caught increased regularly as the dose of lure increased from 1 μg to 5 mg. Males of Orthosia gothica (L.) (Lepidoptera: Noctuidae) were frequently caught in numbers similar to those of P. flammea in the same traps during the flight period of the latter insect. Increasing the relative quantity of the minor component, (Z)-11-tetradecenyl acetate, reduced catches of P. flammea, but not always those of O. gothica.     

The potential for pheromone-based monitoring to predict larval populations of diamondback moth,Plutella xylostella (L.), in canola (Brassica napus L.)

Numbers of adult diamondback moth, Plutella xylostella (L.), captured in pheromone-baited traps may predict the density of damaging larval stages in canola, Brassica napus L. Two years of season-long experiments in Alberta, Canada compared captures of male moths in traps baited with commercial pheromone to larval densities. Significant relationships between moth catch and larval density were infrequent and generally curvilinear indicating that moth numbers were not directly related to larval density. Stronger relationships occurred late season and may indicate that population establishment is necessary before moth capture can predict larval populations. Relationships between moth capture and immature stages sampled at the same time were similar to those sampled two weeks later. A statistically similar number of moths was captured throughout the season in traps baited with lures changed at 6- versus 3-week intervals. During years of moderate and low populations of diamondback moth in canola, moth counts from one pheromone-baited trap per field are sensitive enough to detect densities of immature stages and are more accurate than sweep net sampling. Experiments have contributed to the development of a monitoring system to forecast P. xylostella densities in canola, but research of additional variables may help to develop a consistent relationship between moth catch and larval and pupal densities.     

Disruption of Darna pallivitta (Lepidoptera: Limacodidae) by Conventional and Mobile Pheromone Deployment

Identification of the Darna pallivitta (Moore) pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOn-Bu) has made it possible to investigate communication disruption to control this lepidopteran pest. Conventional communication disruption trials showed marked decreases in the mean number of male moths captured in E7,9-10:COOnBu-treated fields compared with control fields. For traps baited with E7,9-10:COOnBu, percent disruptions were 94.4% and 92.1% for septa (1 g pheromone/ha, 1-wk trial duration) and spirals (6 g pheromone/ha, 8-wk trial duration) respectively. For traps baited with virgin female moths, percent disruption was 73.3% using septa disruptors (1 g pheromone/ha, 1-wk trial duration). Mobile communication disruption using Bactrocera cucurbitae (Coquillett) as carriers for E7,9-10:COOn-Bu was evaluated in the following three areas: fly survivorship, attraction of male moths to treated flies, and moth disruption in a small-scale field trial. Topical application of E7,9-10:COOnBu showed no significant decrease in survivorship at 50 and 80 µg/fly. However, decreased survivorship was observed at 100 µg/fly and linear regression showed E7,9-10:COOnBu dose was significantly correlated with B. cucurbitae survivorship. Traps containing honey–pheromone-fed flies attracted and caught D. pallivitta over a 1-wk period, demonstrating the attractiveness of the carrier. Releasing E7,9-10:COOnBu-fed B. cucurbitae (∼2 g pheromone/ha, 1-wk trial duration) resulted in significantly reduced trap catches in treatment fields compared with control fields on the first 2 d of the field trial. Percent disruptions were 84.7% (day 1) and 56.0% (day 2). These results suggest that both conventional communication disruption and mobile communication disruption have potential to control D. pallivitta.     

水稻二化螟性信息素技术：粘胶诱捕器、性诱剂保存期和剂量

对不同剂量、不同保存期的性诱剂和几种常见诱捕器进行了田间诱蛾效果比较研究。结果表明,诱芯所含的性诱剂的剂量以300 μg为宜;在低温条件下保存1年对其诱蛾效果影响不大;泥盆诱捕器的诱蛾效果不理想,粘胶诱捕器的诱蛾效果也不及水盆诱捕器,但操作较为方便;在田间设置时,其适宜高度需随水稻高度而变化。     

Pest behaviour insights from quarantine surveillance of male Queensland fruit fly,Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

Fruit flies (Diptera: Tephritidae) are a major problem for Australia's $6.9 billion horticultural industry. Bactrocera tryoni (Froggatt) is the most significant fruit fly pest in the eastern states of Australia. Catches of male B. tryoni from cuelure-baited Lynfield surveillance traps in towns bordering the Fruit Fly Exclusion Zone in New South Wales, Australia, from November to May in 2001/2002–2007/2008 were analysed with respect to year, town, property type (urban/rural), and tree species/crop varieties in which the trap was placed (tree type). Average catches of all traps were highest in 2007/2008 and lowest in 2003/2004, and showed an overall positive correlation with rainfall (P < 0.05). More B. tryoni males were caught in Wagga Wagga and Lockhart than in other towns. There were no significant differences in catches of B. tryoni between urban and rurally located traps. With respect to tree type, traps placed in pomefruit trees caught significantly more flies than those in citrus, stonefruit, or nonfruit trees, with no significant differences among the latter three tree groups. Within the pomefruit group, traps in apples (Malus domestica Borkh.) and pears (Pyrus spp.) caught significantly more flies than those in cotoneasters (Cotoneaster spp). Within the citrus group, traps in orange trees (Citrus × sinensis (L.) Osbeck) caught significantly more flies than those in mandarin trees (Citrus reticulata Blanco). No significant differences were detected in catches between any members of the stonefruit group. Within the nonfruit group, traps placed in kurrajongs (Brachychiton populneum (Schott & Endl.) R. Br.) caught significantly more flies than those placed on other tree species in the group. This study demonstrates that although surveillance programs conducted to establish and/or maintain area freedom from specific pests may not provide balanced datasets, careful analysis of the results of such programs can provide valuable insights into the behaviour of the species in question.     

Colonization of rice fields by Nilaparvata lugens (Stål) and its control using a trap crop

Colonization of rice fields by the brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae), was monitored using yellow pan oil-water traps. In approximately 3 months, 35 788 immigrant macropters (1·0 ♂: 1·2 ♀) were caught in 512 traps installed over a 0·352 ha rice field. The trend of daily trap catches conformed closely to the number of macropters visually counted on rice hills. In sub-plots with a trap crop planted 20 days earlier than the main crop on a quarter of the total crop area, more macropters were recorded on trap-crop than on main-crop rows up to about 75 days after transplanting the main crop. In control sub-plots with one planting, more hoppers arrived on the middle than on the border rows. A blanket spray application of Perthane (0·75 kg a.i./ha) was made on the crop in control sub-plots, whereas only the trap crop was sprayed in trapped sub-plots. The combined yield in each treatment with trap crop was significantly higher than in the control treatment.     

茶毛虫性信息素对茶毛虫防治效果研究

在贵州湄潭茶场和平坝茶场研究了茶毛虫性信息素引诱剂大面积诱杀茶毛虫的效果,结果表明,茶毛虫性信息素引诱剂以B型效果最好,42天内两地每盆每晚平均可诱到3.41头和7.51头,最高可诱到198头,大面积使用区内茶毛虫雌蛾怀卵量比对照区减少93.50%,卵块减少85.21% ,幼虫数量减少81.15%,说明茶毛虫性信息素引诱剂诱蛾效果非常明显。     

Pheromone-mediated mating disruption in the millet stem borer, Coniesta ignefusalis (Lepidoptera: Pyralidae)

The millet stem borer, Coniesta ignefusalis Hampson (Lepidoptera: Pyralidae), is a major pest of pearl millet in the Sahelian region of Africa. The female sex pheromone has been identified and synthesised, and previous research had shown that the synthetic pheromone could cause high levels of reproductive communication disruption in small plots when released at rates of 640 mg/ha/day, using PVC resin formulation renewed every seven days to maintain efficiency. In the present research, in experiments in farmers’ fields in Niger, 86.8% (SE = 2.6%) communication disruption was achieved when polyethylene vials loaded with 0.5 mg pheromone at 400 dispensers/ha were used and replaced every 21 days. Polyethylene vials loaded with 80 mg pheromone gave uniform, zero-order release at approximately 0.05 mg/day at 27 °C. Experiments carried out on replicated 0.5 ha plots in farmers’ fields in Niger using a single application of these dispensers at 400 dispensers/ha resulted in at least 99% suppression of pheromone trap catches of male C. ignefusalis moths in treated plots relative to numbers in untreated plots for up to 3 months. However, sampling the central portions of these plots before and after harvest showed no significant differences in infestation, damage or yield loss between plots treated with pheromone and untreated plots. This may have been because of small plot size and the immigration of mated female moths into the treated plots which negated any reduction of mating of females within the treated plots. Comparisons of numbers of male C. ignefusalis moths in traps baited with the standard 0.5 mg monitoring lures and those baited with the 80 mg disruption dispensers showed catches in the latter were only 10-20% of those in the former; indicating high level communication disruptions in traps with high dose dispensers. Implications of using insect synthetic pheromones in the development of integrated management of C. ignefusalis in pearl millet cropping systems in the Sahel are discussed.     

The Technical and Performance Characteristics of a Low-Cost,Simply Constructed,Black Light Moth Trap

The universal mercury vapor black light trap is an effective device used for collecting moth specimens in a wide variety of habitats; yet, they can present challenges for researchers. The mercury vapor trap is often powered by a heavy automotive battery making it difficult to conduct extensive surveys in remote regions. The mercury vapor trap also carries a considerable financial cost per trap unit, making trapping challenging with low research budgets. Here, we describe the development and trapping properties of a lighter, simply constructed, and less expensive trap. The LED funnel trap consists of a funnel, soda bottles with plastic vanes, and is powered by rechargeable 9-V batteries. Two strips of low-wavelength LEDs are used as attractants. We tested the trapping parameters of this trap design compared to a standard mercury vapor trap over 10 trap nights in a suburban woodlot in the summer of 2015. The mercury vapor trap caught significantly more moth individuals than the LED trap (average of 78 vs 40 moths per trap night; P < 0.05), and significantly more species than the LED trap (23 vs 15 per trap night; P < 0.05); the mercury vapor trap caught a total of 104 macromoth species over the duration of the study, compared to a total of 87 by the LED trap. Despite the lower yields, the low cost of the LED trap (<$30 ea.) makes it superior to the mercury vapor trap in cost-acquisition per moth species and per moth individual trapped. The LED trap may be a viable alternative to the standard mercury vapor trap, facilitating insect trapping in more diverse settings.     

Color preference,seasonality, spatial distribution and species composition of thrips (Thysanoptera: Thripidae) in northern highbush blueberries

We investigated color preference, seasonal abundance, spatial distribution and species composition of thrips in northern highbush blueberries, Vaccinium corymbosum L., in New Jersey (USA). White sticky traps were more attractive to thrips compared with yellow or blue traps. Thrips captures using white sticky traps showed that their flight activity begins 20–30 d after the onset of flowering, with 10, 50 and 90% of trap captures observed at 383, 647 and 1231 degree-day accumulations, respectively (10 °C base temperature). Two methods were used to study thrips distribution within a blueberry bush. First, white sticky traps were placed within the bush canopy at three different heights. The highest numbers of thrips were caught on traps in the middle and top one-third of the canopy while the lowest numbers were caught in the bottom one-third. A second method determined the distribution of thrips on the blueberry plant at different heights and phenological stages. The highest numbers of thrips were found on young leaves at lower parts of the canopy, whereas flowers and fruit had fewer thrips and none were found on buds; these thrips were identified as, Scirtothrips ruthveni (88% of adults) and Frankliniella tritici (12%). The distribution of thrips within a blueberry planting was investigated using an evenly-spaced grid of white sticky traps in combination with on bush beating-tray samples. Thrips counts from traps correlated with direct counts on the bush across the entire blueberry field (macro-scale level); however, within the field (micro-scale level), there was no correlation between the number of thrips on traps and on individual bushes near traps. Early in the season, trap counts were higher on bushes closer to the forest, indicative of movement of thrips from wild hosts into blueberry fields. However, this was not the case for direct on bush counts or trap counts for the later part of the season, where there was no clear forest “edge” effect. Percent fruit injury due to thrips feeding was low, and it correlated with thrips counts on bushes but not from counts on traps. Overall, our data show that thrips counts on sticky traps need to be interpreted with care because these numbers weakly correlated with the numbers of thrips on bushes at the micro-scale level and percent fruit injury; however, they can be useful predictors of thrips activity across entire blueberry fields (macro-scale).     

Effects of pigment glands and gossypol on growth,development and insecticide-resistance of cotton bollworm (Heliothis armigera (Hübner))

Cotton bollworm (Heliothis armigera) is a major pest of cotton and other crops. It is important to understand the mechanisms of insecticide tolerance of cotton bollworm on cotton cultivars with host plant resistance to this insect pest. The objectives of this study were to investigate the effects of cotton pigment glands and their gossypol on the growth, development and insecticide tolerance of cotton bollworm. Three pairs of cotton isogenic lines with glanded versus glandless leaves, as well as artificial diets with 5 levels of gossypol, were used to raise cotton bollworm larvae for five generations. The growth, development and insecticide tolerance of larvae were studied. The results indicated that the cotton pigment glands and higher levels of gossypol resulted in a significant decrease in larval weights and moth eclosion rates and delayed the development of larvae and pupae. Larvae that fed on glanded cotton leaves were significantly more tolerant to two insecticides, cyhalothin and monocrotophos, than those fed on glandless cotton leaves. LD₅₀ values were only increased where they were in amount per unit body weight, and not where were calculated in amount per individual. Also the insecticide tolerance of cotton bollworm larvae increased as the gossypol content was raised from 0 to 0.225% in artificial diets. Meanwhile, the activities of two detoxifying enzymes, carboxylesterase and glutathione s-transferase, were significantly higher in the larvae fed on glanded cotton leaves than those fed on glandless cotton leaves. The activities of two enzymes also increased greatly with the increase of gossypol content from 0 to 0.225% in artificial diets. Across 5 generations of feeding and investigation, the significant inhibition effect on larval growth and larval tolerance to two pesticides were found to be only associated with the feeding by current generation, but were not related to previous diets. The activities of two detoxifying enzymes in larvae were also not enhanced significantly when they were fed continuously on glanded cotton leaves or artificial diet with high gossypol. These results indicated that pigment glands and higher levels of gossypol not only inhibited the growth of cotton bollworm larvae but also enhanced their insecticide tolerance. However, the inhibition effect and enhanced insecticide tolerance were inducible but could not be accumulated or inherited. These results will help us better understand the interaction and co-evolution of insecticide tolerance in larvae of cotton bollworm and host chemical components, and also has provided useful information on cotton bollworm management in cotton production, especially in glandless cotton.     

Efficacy and stability of sex-attractant lures for Cydia nigricana (F.) and Cydia medicaginis (Kuzn.)

Field experiments are described in which sex-attractant lures for male pea moth, Cydia nigricana (F.), were compared in the UK and France, to explain earlier anomalies between results in the two countries. These were caused by differences in formulation, rather than in trap design or crop; there was no evidence for the existence of different biological races. Freshly exposed lures containing (E,E)-8,10-dodecadien-1-yl acetate (E,E8,10–12:Ac) from France (INRA) or the UK (Rothamsted) attracted similar numbers of moths in both countries, but the INRA lures rapidly became less attractive because they did not contain antioxidant to prevent the formation of a product repellent to male moths. The experiments in France also confirmed that E,E8,10–12:Ac is a more powerful attractant than (E)-10-dodecen-1-yl acetate for the pea moth, in agreement with previous results in the UK. Similar experiments, only in France, with the lucerne moth, Cydia medicaginis (Kuzn.), confirmed that E,E8,10–12:Ac is a powerful attractant, and showed that field-exposed E,E8,10–12:Ac is repellent to this species also.     

Monitoring and action threshold determination for the obscure mealybug Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) using pheromone-baited traps

The absence of effective pest monitoring has resulted in an increase in populations of the obscure mealybug Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) in pome fruit orchards in the Western Cape Province of South Africa recently. The sex pheromone for P. viburni was recently identified and synthesized. Flight activity of adult male P. viburni was monitored by placing and servicing three, evenly spaced pheromone-baited traps per orchard in three pome fruit growing regions used for the study. Fortnightly fruit sampling was done by randomly picking three fruits per tree for the duration of each fruit season, dissecting and noting mealybug infestation. The biweekly male P. viburni trap catch information and fruit infestation data collected over two seasons were correlated. There was a positive and significant relationship between the fruit infestation and number of P. viburni adult males caught in pheromone-baited traps (r² = 0.454, P < 0.001). The action threshold level was estimated to be 2.5 male P. viburni caught per trap per fortnight at an economic threshold of 2% fruit infestation. This monitoring method was less labor intensive, more accurate and quicker than the current visual sampling and monitoring techniques.     

Study of gene effects for cotton yield and Verticillium wilt tolerance in cotton plant (Gossypium hirsutum L.)

Verticillium wilt (VW), caused by Verticillium dahliae Kleb., is a destructive disease of cotton (Gossypium hirsutum L.). The use of resistant cultivars has long been considered the most practical and effective mean of control. The aim of this work was to study the quantitative genetic basis of Verticillium wilt resistance in Upland cotton by using five genotypes and their possible crosses without reciprocals selecting simultaneously for resistance and desirable agronomic characteristics. Five cotton cultivars and 10 F1s from half-diallel crosses were analyzed for VW resistance. The seed cotton yield, the number of bolls/ plant, and boll weight were measured and Verticillium wilt index (VWI) was estimated during two crop seasons in two different sites each year always on plots with naturally infested soil. Genetic components of variance were analyzed using the Hayman model. Analysis of variance for all characters showed significant differences between genotypes, without genotype-site interaction in most cases. Both, additive genetic variance component (D) and dominance genetic variance components (H1 and H2) were presented in all characters, except for VWI. D was the most important component for boll weight and VWI. Boll weight was the most correlated character with seed cotton yield and VWI. Broad sense heritability was high for boll weight and VWI, moderate for seed cotton yield and low for bolls per plant. Narrow sense heritability was moderate for boll weight, and high for VWI.     

Pre-harvest survival of codling moth in artificially infested sweet cherry fruits

Prior to the 2009 season, sweet cherry fruits, Prunus avium (L.) L., from North America were required to be fumigated with methyl bromide before being exported to Japan to eliminate possible infestation by codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae). However, based on recent biological research on host status, a new procedure (the “systems approach”) was implemented relying on the cumulative effects of pre- and post-harvest practices to produce pest-free sweet cherry fruits for export. This is an organized process that involves the integration of procedures used in the production, harvest, packaging, and distribution of a commodity which cumulatively meet the requirements for quarantine security. The objective of our study was to provide additional information to support the systems approach for codling moth in sweet cherries fruits. For four seasons, branches with sweet cherry fruits were caged on trees and infested by released ovipositing codling moths into the cages. Fruits were sampled weekly for codling moth individuals at each life stage. Eggs were laid mostly on leaves with the seasonal average numbers per cage ranging from 142 to 617. Populations declined rapidly after egg eclosion, with <1.5% of the original cohort surviving to fifth instars. Even after 8 weeks, none had formed cocoons or pupated. This failure of the codling moth to complete a life cycle under field conditions supports previous life history studies and demonstrates that sweet cherry fruits are inadequate hosts for codling moth.     

Development of site-specific IPM against European grapevine moth Lobesia botrana (D. & S.) in vineyards

The aim of this study was to evaluate the potential for site-specific IPM of the European grapevine moth, Lobesia botrana (Denis & Shiffermüller), in a Mediterranean agricultural landscape in central Italy. In 2005-2006, sampling was conducted to verify the spatio-temporal distribution of L. botrana eggs, larvae and adult populations in the investigated agro-ecosystem. On the basis of these results, we applied tactics in 2007 and 2008 to reduce the outer source of the infestation by establishing a pheromone trap barrier system to prevent the movement of male adults from the olive groves into the vineyards, and to test the hypothesis that a within-field site-specific control results in reduced insecticide requirements compared with a traditional uniform IPM protocol. Sampling and control operations were carried out to avoid an increase of economic and labour efforts, leaving as much as possible the costs at the same level of a standard monitoring program. The results highlighted that male hot spots in olive groves disappeared, and that the number of larval nests on vine inflorescences was significantly decreased, when additional traps were deployed (2007-2008) compared to the period before (2005-2006). The site-specific control, i.e. treating only egg hot spots with Bacillus thuringensis var. kurstaki, allowed for a decrease in the surface of the treated vineyard and, consequently, the quantity of insecticide utilised. In 2008, no significant differences between uniform and site-specific IPM in vineyards were observed in the number of damaged berries and the percentage of infested bunches. The results are discussed with respect to the spatial pattern of pest populations, site-specific IPM tactics, sampling operations and pest control costs.     

Cotton-pest management in Egypt

Cotton (Gossypium barbadense L.) in Egypt is attacked by various pests and diseases during the different stages of its development. The cotton leafworm (Spodoptera littoralis (Boisduval)), the pink bollworm (Pectinophora gossypiella (Saunders)) and the American bollworm (Heliothis armigera (Hübner)) are the primary pests of cotton causing most damage. The system of cotton pest management adopted in Egypt is described in relation to the economic thresholds of infestation of various species. The management system includes cultural, mechanical and chemical control methods.     

冀东地区亚洲玉米螟化性探讨

在冀东地区全年分别对亚洲玉米螟田间落卵量、越冬幼虫数量及黑光灯诱蛾量进行调查和统计。结果表明,亚洲玉米螟在冀东地区玉米田全年共发生以3化性为主的不完全世代。亚洲玉米螟在春玉米田发生第1代和第2代,在夏玉米田发生第2代和第3代。统计显示,玉米秸秆中越冬幼虫以3化性为主,3化性幼虫占幼虫总数的73.7%;黑光灯逐日诱蛾量分析显示,全年共形成3个较集中的诱蛾量动态,共诱集成虫1589头,黑光灯全年诱蛾量动态与玉米螟田间落卵量呈极显著相关。