Richard Hilton

Optimizing biocontrol using phenological day degree models: the European earwig in pipfruit orchards

1 Phenological day degree models are often used as warning systems for the emergence of arthropod pests in agricultural crops or the occurrence of natural enemies of the pest species. In the present study, we report on a case study of the European earwig Forficula auricularia L., which is an important natural enemy in pipfruit orchards, and describe how such a day degree model can be used to avoid negative effects of crucial orchard management, such as spray applications and soil tillage. A precise timing of these interventions in relation to the phenology of natural enemies will enhance biocontrol. 2 Earwig population dynamics are characterized by single‐ and double‐brood populations, each with specific biological characteristics. 3 A day degree model capable of predicting the phenology of local earwig populations of both population types was developed. The model was checked for accuracy by comparing the first field observation dates of various life stages with predicted values using temperature data from the nearest weather station. In addition, variation in development time was assessed using field data. 4 The model was able to make predictions on a global scale. Although single‐ and double‐brood populations differ in phenology, the predictions of first appearance dates were similar. Variation in development time showed that single‐brood populations were more synchronized. 5 Our phenological model provides an accurate tool for predicting and simulating earwig population dynamics, as well as for enhancing the biocontrol of pests in pipfruit orchards.

Predicting the emergence of the codling moth, Cydia pomonella (Lepidoptera: Tortricidae), on a degree-day scale in North America

BACKGROUND Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a major pest of apple, pear and walnut production in North America. Management programs are based on preventing larval entry into the fruit or nut and are typically timed by heat-driven models that are synchronized to field populations by first capture of overwintering moths in pheromone traps. Unfortunately, trap capture is affected by a range of environmental parameters as well as by the use of mating disruption, which makes detecting first flight difficult, thus complicating implementation of management programs. The present goal was to evaluate data collected from a broad range of locations across North America to see whether average first spring emergence times could be predicted. RESULTS Average emergence time on a degree-day scale from 1 January was predictable using latitude and elevation. Sites at elevations of <400 m fit a simple quadratic equation using latitude, but, when higher elevations were included, a multiple regression using elevation was required. CONCLUSIONS The present models can be used to simplify management programs for codling moth in areas where heat-driven models that require extensive trapping to synchronize with emergence are currently used.

Evaluating the use of phenylacetonitrile plus acetic acid to monitor Pandemis pyrusana and Cydia pomonella (Lepidoptera: Tortricidae) in apple

Abstract Recent studies have demonstrated that key herbivore-induced foliage volatiles from apple, Malus domestica Borkhausen (Rosaceae), can be attractive to conspecific adult male and female tortricid leafrollers when used together with acetic acid lures. Our study reported here was conducted in Washington State during 2013–2014 and assessed the attractiveness of both sexes of the leafroller, Pandemis pyrusana Kearfott (Lepidoptera: Tortricidae), to blends of acetic acid with phenylacetonitrile. Interestingly, traps baited with phenylacetonitrile plus acetic acid caught significantly more males, females, and total moths than the number of males caught in traps baited with a commercial sex pheromone lure. The evaporation rate of the acetic acid co-lure was shown to be an important factor affecting catches of P. pyrusana with phenylacetonitrile. Adding phenylacetonitrile to traps baited with pear ester, ethyl (E, Z)-2,4-decadienoate and acetic acid significantly reduced both total and female moth catches of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae). However, neither C. pomonella nor P. pyrusana catch were impacted when phenylacetonitrile and acetic acid were added to traps baited with pear ester plus (E, E)-8,10-dodecadien-1-ol, the sex pheromone of codling moth. These results support our broader work to develop lures to improve monitoring and management of a number of tortricid pests attacking horticultural crops worldwide.

Halyomorpha halys (Hemiptera: Pentatomidae) Response to Pyramid Traps Baited with Attractive Light and Pheromonal Stimuli

Abstract Halyomorpha halys Stål (Hemiptera: Pentatomidae) is an invasive insect that causes severe economic damage to multiple agricultural commodities. Several monitoring tools, including pheromone and light-baited black pyramid traps, have been developed to monitor H. halys. Here, we evaluated the attractiveness of these traps baited with only light, only pheromone, or the combination in comparison with unbaited traps throughout the growing season in regions with high and low H. halys population densities. In regions with high population densities in the Mid-Atlantic, all traps baited with pheromone or lights performed better than control traps. During mid-season, traps containing lights captured more H. halys adults, whereas pheromone-baited traps captured greater numbers during the late season. In low density regions in the Pacific Northwest, traps with lights or pheromone captured more H. halys adults than control traps. In addition, we evaluated the influence of competing light sources associated with anthropogenic structures. When light traps were deployed next to these additional light sources, H. halys captures in pyramid traps baited with light were not significantly reduced. Overall, our results indicate that both light and pheromone traps can be used to detect H. halys activity in low and high density populations.

STIMULATION OF PEAR RUST MITE POPULATIONS DUE TO APPLICATION OF SPINETORAM IN SOUTHERN OREGON AND NORTHERN CALIFORNIA

Spinetoram is currently being used in pears for control of Lepidoptera and other pests. Over the last ten years, results of repeated trials in southern Oregon and northern California examining the effect of spinetoram use in pears have shown elevations in the population level of pear rust mite, Epitrimerus pyri. In both regions, the increase in pear rust mite populations due to the application of spinetoram has been statistically significant in multiple years. In 2013, an evaluation in northern California resulted in both significantly higher levels of pear rust mite throughout the sampling period and significantly higher levels of russet on the fruit at harvest. In the spinetoram treatment, 8.4% of the fruit sampled had greater than ¼ of the fruit surface with russet as compared to 0.2% of the fruit in the untreated check. Reduced levels of some natural enemies have been observed in southern Oregon trials, specifically parasitic hymenoptera, Encarsia sp., and the common earwig, Forficula auricularia. Whether the increase in pear rust mite resulting from spinetoram applications in pear is due to a reduction in natural enemies or to hormoligosis remains undetermined.

Control of the Codling Moth with Experimental Insecticides, 1994

The trial was conducted in a 30-yr-old Bartlett pear block with chemicals applied to four single tree replicates arranged in a randomized block design. Materials were applied with conventional, high pressure hand gun equipment and sprayed to runoff or about 400 gpa. Each chemical was applied 3 times in a season-long, phenologically timed CM program. Two different timings were employed as based on CM biofix as determined by the first male moth captured in pheromone baited traps. A standard larvicidal timing was used in treatments receiving Guthion, AC 303,603 and 1 treatment of RH 5992. This standard program consisted of a first application at about 250 dd following biofix; the second 28 days later and the final at about 1250 dd, or 250 dd after the predicted emergence of second generation moths. Corresponding dates to the above schedule were 12-13 May, 9 Jun and 13 Jul. An ovicidal timing was employed for the insect growth regulator (IGR) fenoxycarb. The timings for fenoxycarb were a first application at 50-100 dd after biofix (27 Apr), the second 28 days after the first, and the third at 1050 dd (7 Jul). Evaluation of CM damage was made by recording the number of larval entries per 50 fruit per replicate per treatment at the end of the first CM generation (7-9 Jul) and again at harvest (17 Aug). Densities of pear psylla (PP) immatures and spider mites [twospotted spider mite (TSM), European red mite (ERM) and pear rust mite, (PRM)] were estimated at 3 posttreatment intervals (20 Jun, 25 Jul, 16 Aug) by recording their numbers from leaf brushing 20 leaves (10 old, 10 new) per replicate. Adult PP and PP predators, consisting of lacewings, earwigs, and predaceous bugs, were estimated from 2 beating tray samples per replicate taken on the following dates: 22 Jun, 27 Jul, and 19 Aug.

Pear, Late Season Evaluation of Agri-Mek in Combination with Spray Adjuvants, 1993

The study was conducted in an 8-year-old commercial Bosc orchard 16.9 acres in size. The orchard block was divided into 8 treatments, replicated three times in a randomized block design. Applications were made 8 Jul using a commercial air-carrier sprayer set to deliver 100 gal/acre. Densities of the PP and TSM were estimated by randomly selecting 10 mature and 10 young leaves 8 days post-treatment and then bi-weekly, brushing the samples and recording the stages and numbers of each species with the aid of a dissecting microscope.