Mating Disruption Programs Research Articles

Sex Pheromone Aerosol Emitters for Lobesia botrana Mating Disruption in Italian Vineyards

Despite the great amount of information on the European Grapevine Moth (EGVM), Lobesia botrana (Lepidoptera: Tortricidae), and the effective strategies available for its management, this moth remains the main key pest damaging grapevines in the Mediterranean and Central Europe wine-growing areas. Synthesizing and manipulating its sex pheromone components fostered the development of new dispensers to boost the effectiveness and sustainability of mating disruption (MD) programs. Recent MD research has highlighted that the effectiveness of aerosol emitters is comparable to that of passive dispensers when applied in large, uniform sites such as Spanish vineyards. However, aerosol emitters that are equally effective in geographical areas characterized by small-sized vineyards, typical of many Italian regions, have not received enough research attention. To face this challenge, herein the experimental aerosol emitter (product code: Isonet® L MISTERX843) was tested at three different application rates (i.e., 2, 3 and 4 units/ha) in three study sites, two in Tuscany (Central Italy in 2017 and 2018) and one in Emilia-Romagna (Northern Italy in 2017), respectively, for a total of five trials. To assess the efficacy of this novel MD aerosol emitter, three different application densities were compared with an untreated control and two grower's standards. The latter were represented by passive (Isonet® L TT) and active (Checkmate® Puffer® LB) release dispensers, already on the market for EGVM MD and applied at, respectively, 200-300 and 2.5-4 units/ha. MD carried out with Isonet® L MISTERX843 led to zero catches of males in the pheromone traps. They also allowed for a significant reduction in the number of infested flower clusters and bunches, as well as in the number of nests per flowers cluster/bunch, if compared to the untreated control. As a general trend, MD effectiveness was fully comparable, or even better, if compared to the grower's standard. In conclusion, our research pointed out that the Isonet® L MISTERX843 can allow for effective EGVM management in small-sized Italian vineyards. Lastly, our economic evaluation showed that the MD whole cost per hectare using active or passive release devices was comparable.

Behavioral Response of Unmated Female Plodia interpunctella Hübner (Lepidoptera: Pyralidae) to Synthetic Sex Pheromone Lure.

Indian meal moth, Plodia interpunctella Hübner, is an important pest of stored products in food facilities like processing plants, warehouses, and retail stores. Mating disruption, which uses synthetic pheromone to delay or prevent mating, is a relatively new management tactic for this pest but is becoming widely adopted. However, little is known about the mechanisms behind its efficacy, including how artificial pheromone impacts female behavior. Here we assay behavioral responses of two strains of unmated female P. interpunctella exposed to pheromone. Results show one strain increased the duration of calling behavior while the other decreased calling when exposed to pheromone lures. Time walking decreased, and time cleaning increased for both strains when exposed to pheromone. Time of first walking behavior was also delayed for one strain when exposed to pheromone. Females of both strains were less mobile when exposed to pheromone. These results show autodetection of pheromone by females, but also indicate that strains may vary in behavioral responses. Differing patterns of calling behavior between strains could be driven by either strain-specific genetic differences or laboratory induced effects. Decreasing calling behavior and overall movement during exposure to pheromone could enhance the effectiveness of a mating disruption program. However, increased calling by females in the presence of pheromone may be a competitive response and could increase mating success under certain scenarios. These findings suggest that artificial pheromone associated with monitoring and mating disruption programs has impacts on female behavior and warrants further study to determine the overall impacts on program effectiveness.

Pheromone Deployment Strategies for Mating Disruption of a Vineyard Mealybug.

The mealybug, Planococcus ficus (Signoret), is a primary vineyard pest in California and other grape-growing regions throughout the World. Mating disruption programs are commercially available to manage Pl. ficus, but widespread adoption has been limited, in part, by high costs compared with insecticide programs. To improve mating disruption economic effectiveness, different deployment technologies (passive, aerosol, and microencapsulated formulations) were individually examined. Adult male Pl. ficus captures in pheromone traps and categorical ratings of vine infestation or crop damage suggest that all deployment strategies lowered mealybug densities or damage. Using passive dispensers, deployment rates of 310 and 465 per ha lowered Pl. ficus crop damage similar to 615 per ha, a rate commonly used in commercial operations; reduced rates would lower product and deployment costs. Meso dispensers, containing more a.i., deployed at 35 per ha did not have a treatment impact, but a microencapsulated formulation and aerosol canisters lowered male flight captures and/or crop damage. Male mealybug flight activity was greatest from 0500–1100 hr, which coincided with temperatures >16° and <32°C. These restricted times and temperatures suggest programable dispensers might allow pheromone deployment to coincide only with flight patterns. A large field trial using passive dispensers found greater treatment separation after 3 yr of pheromone deployment. Discrepancies in results among vineyards may be related to Pl. ficus density, but combined results from all trials suggest that different deployment technologies can be used to impact Pl. ficus densities and damage, even at reduced rates, especially with continued use over multiple seasons.

Effect of Pheromone Blend Components, Sex Ratio, and Population Size on the Mating of Cadra cautella (Lepidoptera: Pyralidae).

The almond moth Cadra cautella (Walker), a key pest of storage facilities, is difficult to manage using synthetic chemicals. Pheromone-based management methods remain a high priority due to advantages over conventional management practices, which typically use insecticides. Cadra cautella females release a blend of pheromone including (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA). The effect of these components on mating of C. cautella and how response varies with the population density and sex ratio remain unknown. In this study, the mating status of C. cautella was studied inside mating cages under different ratios of ZETA and ZTA diluted in hexane and at different population sizes either with equal or unequal sex ratio. The lowest percentage of mated females (highest mating disruption [MD] effects), corresponding to roughly 12.5%, was produced by a 5:1 and 3.3:1 ratio of ZETA:ZTA. Populations with equal sex ratio showed the lowest percentage of mated females, at 20% and 12.5% under lower and higher density, respectively. The next lowest percentage of mated females was produced when the sex ratio was set to 1: 2 and 2:1 male:female, with just 25% and 22.5% of moths mated, respectively. This study shows that mating status of C. cautella is influenced by ZETA:ZTA ratio, sex ratio, and population size. This current knowledge would have useful implications for mating disruption programs.

Development of a Mating Disruption Program for a Mealybug, Planococcus ficus, in Vineyards.

Simple SummaryThe vine mealybug is a key insect pest of vineyards that currently is controlled by one or more insecticide applications per season. Here, we sought to develop a more sustainable control tool by using the mealybug’s sex pheromone to reduce mating and thereby lower pest damage. The mature female mealybug emits a sex pheromone that the winged adult male uses to find and mate with females. Synthetically produced sex pheromone, specific to the vine mealybug, was enclosed in commercial dispensers and deployed in vineyards in 2004–2007 studies to determine if mating disruption could provide a viable control option. Trials were conducted in commercial vineyards with cooperating farmers. Across all trials, mating disruption reduced pheromone trap captures of adult male mealybugs—an indication that the population numbers were lowered—and there was often a reduction mealybug numbers on vines and/or crop damage. There was not a clear reduction in the proportion of female mealybugs with ovisacs (a cottony-like mass containing mealybug eggs), but this may have resulted from the production of non-viable ovisacs that were not differentiated in the field samples. Pheromone trap captures were never lowered to zero (often called trap shut down), possibly because trials were conducted in vineyards with unusually high mealybug densities. Trap capture patterns commonly began low in April-May, increased in mid-July or August, and often decreased in September–October when post-harvest insecticides were applied. Results over all years suggest season-long coverage or late season coverage may be as or more important than dose per hectare. This research was used to help initiate the commercialization of mating disruption products for the vine mealybug, which are now being successfully used throughout the world’s grape-growing regions where this pest is found.The vine mealybug (VMB), Planococcus ficus (Hemiptera: Pseudococcidae), is a key insect pest of vineyards, and improvements in sustainable control of this pest are needed to meet increasing consumer demand for organically farmed products. One promising option is mating disruption. In a series of experiments conducted from 2004 to 2007, we tested the effects of mating disruption on trap captures of Pl. ficus males in pheromone-baited traps, on Pl. ficus numbers and age structure on vines, and on damage to grape clusters. From 2004 to 2005, the effects of dispenser load (mg active ingredient per dispenser) were also assessed, and dispensers were compared to a flowable formulation. Across all trials, mating disruption consistently reduced pheromone trap captures and often reduced mealybug numbers on vines and/or crop damage, regardless of the pheromone dose that was applied. Reductions in Pl. ficus densities in mating disruption plots were not accompanied by clear effects on mealybug population age structure; however, production of non-viable ovisacs by unmated females may have obscured differences in proportional representation of ovisacs. Pheromone trap captures were never lowered to zero (often called trap shut down), possibly because trials were conducted in vineyards with unusually high Pl. ficus densities. Trap-capture patterns in both treated and control plots commonly began low in April–May, increased in mid-July or August, and often decreased in September–October when post-harvest insecticides were applied. During the four-year trial, the release rate from plastic sachet dispensers was improved by industry cooperators as pheromone was released too quickly (2004) or not completely released during the season (2005–2006). The flowable formulation performed slightly better than dispensers at the same application dose. Results over all years suggest season-long coverage or late-season coverage may be as or more important than dose per hectare. Development of a dispenser with optimized season-long pheromone emission or targeted seasonal periods should be a future goal.

Mating Delay Reduces Reproductive Performance but not Longevity in a Monandrous Moth.

Age at mating is one of the most important factors that affect mating success and reproductive fitness in insects. The present study investigated how the age of the two sexes at mating determined mating success, reproductive fitness and longevity in Phauda flammans (Walker) (Lepidoptera: Phaudidae), a serious pest of Ficus spp. trees in South and Southeast Asia. The study may provide basic knowledge for the development of mating disruption programs using sex pheromones to control this pest. The species is monandrous and its adults live for only 4–5 d. We show that delayed mating significantly lowered mating success in both sexes, with males being more severely affected than females. Mating delay also reduced reproductive outputs of both sexes but females were more negatively affected than males. We did not find any effect of delayed mating on longevity of either sex. Our findings suggest that mating disruption with sex pheromones can be an effective method to delay mating in P. flammans, reducing reproductive success and thus limit population growth.

Sex Pheromone Aerosol Devices for Mating Disruption: Challenges for a Brighter Future

Pheromone-mediated mating disruption (MD) represents an important tool to manage insect pests in agriculture and forestry. MD relies on the release of synthetic sex pheromones from dispensers in crops, interfering with mate finding and reproduction of a pest through both competitive and non-competitive mechanisms. MD programs primarily rely upon “passive” dispensers, used at high densities per hectare (200–3000 units∙ha−1). In addition to the labor required for their application, another disadvantage of “passive” dispensers is the continuous release of pheromones, regardless of the time of day or the pest flight activity. Aerosol delivery systems can overcome the drawbacks of passive dispensers as they are applied at far lower density (2–5 units∙ha−1) and they can be programmed to release pheromones at selected time intervals when the target pest is active. However, the mode of action of aerosol dispensers is still not well understood and there are concerns of whether they are as effective as passive dispensers. This review focuses on the history of aerosol dispensers, mode of action, and effectiveness on various crops; deployment strategies; and the movement of pheromone once released. Limitations of aerosols and challenges for future research and commercial use are discussed.

Managing the vine mealybug, Planococcus ficus, through pheromone-mediated mating disruption.

The vine mealybug (VMB), Planococcus ficus (Hemiptera: Pseudococcidae), is a key insect pest of vineyards. While pheromone-based mating disruption (MD) has been successfully tested against a wide range of insect pests, knowledge about its efficacy against key mealybug species, such as P. ficus, is scarce. In this study, a novel MD product, Isonet® PF, was evaluated by testing 300, 400, and 500 dispensers/ha at four study sites located in Northern (Veneto) and Southern (Sicily) Italy. Experiments were carried out over 2years by monitoring the mealybug populations in wine grape and table grape vineyards managed with and without the application of MD. Pheromone dispensers were periodically collected during the grapevine-growing season, extracted, and analyzed by GC-MS, to determine their pheromone content and the release in mg/ha/day. The results showed that use of the MD dispenser Isonet® PF reduced the percentage of VMB-infested bunches and the number of VMB specimens per bunch compared with the untreated controls. This was recorded over 2years at all experimental sites. Differences in the incidence of infested bunches among the three tested rates of Isonet® PF were not detected. Overall, the results presented here contribute to optimizing the sex pheromone dosage used in MD control programs against VMB allowing a reduction of broad-spectrum insecticides currently employed to manage this important pest.

Eco-friendly pheromone dispensers-a green route to manage the European grapevine moth?

The development of environmentally sustainable control strategies to fight insect pests is a key challenge nowadays. Pheromone-mediated mating disruption (MD) is based on the release of synthetic sex attractants into a crop, interfering with mate finding of a given pest species. However, a limited number of research items have been published on the optimization of MD strategies against the European grapevine moth, Lobesia botrana, as well as on the use of biodegradable dispensers to reduce waste production in vineyards, despite the high economic importance of this pest. Therefore, the present study evaluated the efficacy of the MD products Isonet® L TT and the biodegradable Isonet® L TT BIO, applied at various densities, in reducing L. botrana damage on grapevine in comparison to an untreated control and the reference MD product Isonet® L. Experiments were conducted in three different areas of grapevine cultivation, located in Central and Northern Italy, over three different years. Our MD approach allowed a reliable control of the three generations of L. botrana during the whole grape growing season, leading to a significant reduction in the infested flower clusters andbunches, as well as in the number of nests per flower cluster and bunch, if compared to the untreated control. The performances of Isonet® L TT BIO, Isonet® LTT, and Isonet® L did not differ in terms of infested flower clusters/bunches, as well as nests per flower cluster/bunch. This was confirmed in all experimental sites over 3years of field experiments. Overall, the present research provides useful information for the optimization of MD programs against L. botrana, highlighting the interesting potential of biodegradable pheromone dispensers that can be easily applied at low densities in vineyards, reducing the use of chemical pesticides to control moth pests.

Stability of Cacopsylla pyricola (Hemiptera: Psyllidae) Populations in Pacific Northwest Pear Orchards Managed with Long-Term Mating Disruption for Cydia pomonella (Lepidoptera: Tortricidae).

This study focused on conservation biological control of pear psylla, Cacopsylla pyricola, in the Pacific Northwest, USA. We hypothesized that insecticides applied against the primary insect pest, codling moth Cydia pomonella, negatively impact natural enemies of pear psylla, thus causing outbreaks of this secondary pest. Hence, the objective of this study was to understand how codling moth management influences the abundance of pear psylla and its natural enemy complex in pear orchards managed under long-term codling moth mating disruption programs. We conducted this study within a pear orchard that had previously been under seasonal mating disruption for codling moth for eight years. We replicated two treatments, “natural enemy disrupt” (application of two combination sprays of spinetoram plus chlorantraniliprole timed against first-generation codling moth) and “natural enemy non-disrupt” four times in the orchard. Field sampling of psylla and natural enemies (i.e., lacewings, coccinellids, spiders, Campylomma verbasci, syrphid flies, earwigs) revealed that pear psylla populations remained well below treatment thresholds all season despite the reduced abundance of key pear psylla natural enemies in the natural enemy disrupt plots compared with the non-disrupt treatment. We speculate that pear psylla are difficult to disrupt when pear orchards are under long-term codling moth disruption.

Multi-Species Mating Disruption in Cranberries (Ericales: Ericaceae): Early Evidence Using a Flowable Emulsion.

Pheromone-based mating disruption has proven to be a powerful pest management tactic in many cropping systems. However, in the cranberry system, a viable mating disruption program does not yet exist. There are commercially available pheromones for several of the major pests of cranberries, including the cranberry fruitworm, Acrobasis vaccinii Riley (Lepidoptera: Pyralidae) and blackheaded fireworm, Rhopobota naevana (Hübner) (Lepidoptera: Tortricidae). Previous studies have shown that mating disruption represents a promising approach for R. naevana management although carrier and delivery technologies have remained unresolved. The present study examined the suitability of Specialized Pheromone & Lure Application Technology (SPLAT; ISCA Technologies, Inc., Riverside, CA), a proprietary wax and oil blend, to serve as a pheromone carrier in the cranberry system. In 2013 and 2014, we tested a blend of pheromones targeting A. vaccinii and R. naevana in field-scale, replicated trials. Pheromones were loaded into SPLAT and the resulting “SPLAT BFW CFW” formulation was deployed in commercial cranberry marshes. We compared moth trap-catch counts within SPLAT-treated blocks to those of conventionally managed blocks. In 2013, applications of SPLAT BFW CFW resulted in highly successful disruption of R. naevana and promising, though inconsistent, disruption of A. vaccinii. To improve disruption of A. vaccinii, the pheromone load was increased in 2014, providing 92% and 74% reductions in trap-catch for R. naevana and A. vaccinii, respectively. Importantly, larval infestation rates in SPLAT-treated blocks were lower than those of conventionally managed blocks. These results suggest that a multispecies mating disruption system (SPLAT BFW CFW) may represent an effective pesticide-alternative for serious pests of cranberries.

Impact of a long-term mating-disruption management in crops on non-target insects in the surrounding area

Protecting insects in agro-ecosystems may result in substantial benefits assuming that numerous species produce ecological services. The impact of pesticides on non-target insects is a function of the number of treatments, chemical product, amount of active ingredients and the method of application in the fields, together with their persistence in the environment. To reduce the use of these products, several methods of integrated pest management were developed in agriculture. Among them mating-disruption (MD) is widely employed, for example against the codling moth Cydia pomonella L., a key pest in apple orchards. MD should minimize the negative impacts of chemical pest management on non-target insects in the vegetation surrounding the orchards. We investigated this hypothesis in a long-term MD program on insect populations in the edges of managed plots, using five gall-inducing aphid species in 135 Pistacia palaestina trees. The highest aphid species richness was found in trees growing away from orchards followed by trees in orchards close to Kiwi patches which were never sprayed with insecticides. Intermediate aphid species richness was revealed in parcels where MD against codling moth has been carried out during the last 18 years. In these plots, reduced number of chemical treatments was used against secondary pests each year. Trees in orchards with intensive chemical treatment with insecticide had almost no galls. In conclusion, the populations of the five non-target species in the adjacent natural environment did not suffer significantly from the few chemical treatments. The long term MD program of C. pomonella has a minimum disruption on non-target species in the orchards and their immediate surroundings.

Quantifying the Benefits of Areawide Pheromone Mating Disruption Programs that Target Codling Moth (Lepidoptera: Tortricidae)

A 4 yr research and implementation project in Michigan apple production showed that deploying pheromone-mediated mating disruption for codling moth, Cydia pomonella L., in an areawide (AW-CMMD) program where mating disruption is established on all apple-producing acreage on individual and adjacent farms significantly improves control of codling moth. The areawide project was compared with mating disruption applied to individual apple blocks (Block-CMMD) on farms with other orchard acreage not under disruption, or apple blocks not treated with mating disruption (No-CMMD). Pheromone-baited traps were deployed at 1/ha over 850 ha of AW-CMMD and 16 ha of Block-CMMD; 16 ha were not treated. Average captures of codling moth in AW-CMMD declined each season and were lower than in the Block-CMMD and the No-CMMD programs. Captures of male codling moth in pheromone-baited traps were reduced 93% by year 4 of the project in AW-CMMD orchards. Injury to fruit and the overall number of insecticides targeting codling moth decreased each year in the areawide program; in Block-CMMD orchards, injury levels remained about the same with slight reductions in insecticide use from year, and in the No-CMMD orchards, injury increased significantly, but insecticide use varied little from year to year. Growers who implemented AW-CMMD realized a mean savings of $55–65/ha through reduced fruit injury and use of insecticides as compared with orchards using insecticide-only programs. This Michigan project demonstrates that an areawide approach to mating disruption improves the benefits of deploying pheromone in individual blocks.

Effect of Varying Dispenser Point Source Density on Mating Disruption of &lt;I&gt;Grapholita molesta&lt;/I&gt; (Lepidoptera: Tortricidae)

Hand-applied dispensers are successfully used in mating disruption programs, but cost of labor to apply these dispensers limits their adoption. Creating hand-applied dispensers that release larger amounts of pheromone and that can be applied at lower densities per hectare could reduce the cost of mating disruption and increase its use. The effect of reducing the number of point sources per hectare while keeping the amount of pheromone applied per hectare constant on the success of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) mating disruption was investigated with Confuse-OFM, paraffin disk, and Isomate-M Rosso dispensers. For all dispensers, as point source density decreased, numbers of moths captured increased, percentage of orientation disruption to traps decreased, and variability in these measures increased. Decreasing point source density, even while keeping the amount of pheromone applied per hectare constant is not a viable option for reducing the cost of G. molesta mating disruption with hand-applied dispensers. Puffers (aerosol dispensers) are applied at 2.5-5 dispensers per ha for G. molesta control. However, hand-applied dispensers fail when clumped at such low numbers of release sites. Potential explanations for the success of Puffers and the failure of hand-applied dispensers at very low point source densities are presented. The utility of paraffin disk dispensers as experimental devices also is discussed.

Ground Beetle (Coleoptera: Carabidae) Assemblages in Apple Orchards Receiving Pheromone-based or Conventional Tortricid Management Programs

Pitfall trapping was used to assess the effect of a low-spray mating disruption program targeted against the codling moth and leafrollers on carabid communities (potential predators of codling moth, Cydia pomonella [L.], leafrollers [Lepidoptera: Tortricidae] and apple maggot, Rhagoletis pomonella [Walsh]) in the orchard ground cover. Abundance and species richness of carabids were generally higher in mating disruption blocks relative to conventionally-managed blocks. Over 2 yrs, 3,173 carabids representing 62 species in 27 genera were collected. The most common carabids (more than 5% of the total carabid population) were Harpalus pensylvanicus (DeGeer) (38.2%), Harpalus erythropus Dejean (11.4%), Poecilus lucublandus (Say) (10.1%), Dicaelus elongatus Bonelli (6.2%) and Harpalus longicollis LeConte (5.9%).

Sprayable Microencapsulated Sex Pheromone Formulation for Mating Disruption of Oriental Fruit Moth (Lepidoptera: Tortricidae) in Australian Peach and Pear Orchards

Areawide mating disruption treatments have been effective in controlling infestation of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), in Australian pome and stone fruit orchards. Although successful, the areawide mating disruption program has been an expensive approach by using hand-applied Isomate dispensers. Sprayable microencapsulated (MEC) pheromone formulations that can be applied with standard spray equipment could substantially reduce the cost of application. Field trials conducted during two consecutive seasons (2002-2004) demonstrated that monthly applications of MEC-OFM phase V (3M Canada, London, Ontario, Canada) at a rate of 125 ml/ha (37.1 g [AI]/ha) in replicated 2-ha blocks of both peaches and pears reduced oriental fruit moth shoot tip and fruit damage as effectively as a single application of Isomate OFM Rosso hand-applied dispensers (500 dispensers per ha) and as or more effectively than standard broad-spectrum insecticide sprays. Fruit protection was achieved despite high oriental fruit moth population densities in both crops as measured by moth catches in terpinyl acetate food and pheromone traps. Similar numbers of oriental fruit moths were captured among all treatments in food traps but captures of males in pheromone traps were disrupted (96-99%) in pheromone-treated blocks relative to controls. The results of this study suggest that microencapsulated formulations of pheromone could be effectively used in areawide mating disruption programs for oriental fruit moth in Australia as a cost-saving alternative to reservoir-style dispensers requiring labor-intensive hand application.

Pheromone-Based Mating Disruption of &lt;I&gt;Planococcus ficus&lt;/I&gt; (Hemiptera: Pseudococcidae) in California Vineyards

Experiments were conducted to test a mating disruption program for the mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) in California vineyards. The sprayable, microencapsulated formulation of the racemic sex pheromone lavandulyl senecioate was applied with an air-blast sprayer, using three and four applications in 2003 and 2004, respectively. Mating disruption was combined with an application of buprofezin (2004) in June. Compared with a no-pheromone control, there were significantly lower season-long trap catches of adult males, season-long mealybug densities (2003 only), and crop damage in mating disruption plots. The amount of mealybug reduction and mechanisms that resulted in lower crop damage in mating disruption plots is discussed. In samples taken during the growing season (April to September), mealybug density was only 12.0 +/- 15.6 and 31.1 +/- 11.6% lower in the mating disruption plots than in control plots in 2003 and 2004, respectively. In the mating disruption treatment, mealybug egg production was significantly lower (2003 only), as were the proportion of ovisacs and crawlers produced. There was no treatment impact on percentage of parasitism. Mealybug density influenced treatment impact. In 2004, vines were categorized as having low, medium, or high mealybug densities during a preapplication survey. After treatment application, mealybug density was reduced by 86.3 +/- 6.3% on vines in the low mealybug density category, but it was unchanged on vines in the high density category. Another factor that reduced treatment impact was the relatively short effective lifetime of the sprayable formulation.

Factors Affecting Entomopathogenic Nematodes (Steinernematidae) for Control of Overwintering Codling Moth (Lepidoptera: Tortricidae) in Fruit Bins

Fruit bins infested with diapausing codling moth larvae, Cydia pomonella (L.), are a potential source of reinfestation of orchards and may jeopardize the success of mating disruption programs and other control strategies. Entomopathogenic nematodes (EPNs) were tested as a potential means of control that could be applied at the time bins are submerged in dump tanks. Diapausing cocooned codling moth larvae in miniature fruit bins were highly susceptible to infective juveniles (IJs) of Steinernema carpocapsae (Weiser) and Steinernema feltiae (Filipjev) in a series of experiments. Cocooned larvae are significantly more susceptible to infection than are pupae. Experimental treatment of bins in suspensions of laboratory produced S. feltiae ranging from 10 to 100 IJs/ml of water with wetting agent (Silwet L77) resulted in 51–92% mortality. The use of adjuvants to increase penetration of hibernacula and retard desiccation of S. feltiae in fruit bins resulted in improved efficacy. The combination of a wetting agent (Silwet L77) and humectant (Stockosorb) with 10 S. feltiae IJs/ml in low and high humidity resulted in 92–95% mortality of cocooned codling moth larvae versus 46–57% mortality at the same IJ concentration without adjuvants. Immersion of infested bins in suspensions of commercially produced nematodes ranging from 10 to 50 IJs/ml water with wetting agent in an experimental packing line resulted in mortality in cocooned codling moth larvae of 45–87 and 56–85% for S. feltiae and S. carpocapsae, respectively. Our results indicate that EPNs provide an alternative nonchemical means of control that could be applied at the time bins are submerged in dump tanks at the packing house for flotation of fruit.

Factors Affecting Entomopathogenic Nematodes (Steinernematidae) for Control of Overwintering Codling Moth (Lepidoptera: Tortricidae) in Fruit Bins

Fruit bins infested with diapausing codling moth larvae, Cydia pomonella (L.), are a potential source of reinfestation of orchards and may jeopardize the success of mating disruption programs and other control strategies. Entomopathogenic nematodes (EPNs) were tested as a potential means of control that could be applied at the time bins are submerged in dump tanks. Diapausing cocooned codling moth larvae in miniature fruit bins were highly susceptible to infective juveniles (IJs) of Steinernema carpocapsae (Weiser) and Steinernema feltiae (Filipjev) in a series of experiments. Cocooned larvae are significantly more susceptible to infection than are pupae. Experimental treatment of bins in suspensions of laboratory produced S. feltiae ranging from 10 to 100 IJs/ml of water with wetting agent (Silwet L77) resulted in 51-92% mortality. The use of adjuvants to increase penetration of hibernacula and retard desiccation of S. feltiae in fruit bins resulted in improved efficacy. The combination of a wetting agent (Silwet L77) and humectant (Stockosorb) with 10 S. feltiae IJs/ml in low and high humidity resulted in 92-95% mortality of cocooned codling moth larvae versus 46-57% mortality at the same IJ concentration without adjuvants. Immersion of infested bins in suspensions of commercially produced nematodes ranging from 10 to 50 IJs/ml water with wetting agent in an experimental packing line resulted in mortality in cocooned codling moth larvae of 45-87 and 56 - 85% for S. feltiae and S. carpocapsae, respectively. Our results indicate that EPNs provide an alternative nonchemical means of control that could be applied at the time bins are submerged in dump tanks at the packing house for flotation of fruit.

Fumigation of Empty Fruit Bins with Carbon Dioxide to Control Diapausing Codling Moth Larvae and Penicillium expansum Link. ex Thom Spores

Wooden fruit bins are a source of diapausing codling moth and postharvest pathogenic fungi. The redistribution of codling moths within bins is a problem where codling moth populations are being controlled by areawide codling moth sterile release programs, mating disruption programs, or both. Laboratory and fumigation chamber trials were carried out to determine the impact of relatively low levels of carbon dioxide on late-instar codling moth (Cydia pomonella L.) and two postharvest fruit pathogens, Penicillium expansum Link ex Thom and Botrytis cinerea Pers. ex Fr. Fumigation of diapausing codling moth with 40% CO2 in laboratory trials resulted in over 60% mortality after only 6 days of exposure and mortality increased with time of exposure. Significant mortality (68%) of diapausing codling moth larvae occurred after 14 days of exposure in the laboratory to 13% CO2 and a mean of 88% mortality was recorded after fumigation for 20 days. A significant number of P. expansum (46%) spores failed to germinate after laboratory exposure to 13% CO2 for 12 and 18 days respectively. Close to 100% of the P. expansum spores failed to germinate by day 20. When diapausing codling moth larvae and spores from both plant pathogens were placed in wooden fruit bins and fumigated for 21 days at 13% CO2, 75% of the diapausing codling moths died and 80% of the P. expansum spores failed to germinate. No effect on B. cinerea was observed.