David R. Haviland

Evaluation of Monitoring Traps for Drosophila suzukii (Diptera: Drosophilidae) in North America

ABSTRACT Drosophila suzukii Matsumura (Diptera: Drosophilidae), a recent invasive pest of small and stone fruits, has been detected in more than half of the U.S. states, and in Canada, Mexico, and Europe. Upon discovery, several different trap designs were recommended for monitoring. This study compared the trap designs across seven states/provinces in North America and nine crop types. Between May and November 2011, we compared a clear cup with 10 side holes (clear); a commercial trap with two side holes (commercial); a Rubbermaid container with mesh lid and rain tent (Haviland), and with 10 side holes and no tent (modified Haviland); a red cup with 10 side holes (red); and a white container with mesh lid and rain tent (Van Steenwyk). Although fly catches among traps varied per site, overall, the Haviland trap caught the most D. suzukii, followed by the red, Van Steenwyk, and clear trap. The modified Haviland and commercial trap had low captures. Among five crop types in Oregon, a clear cup with mesh sides (Dreves) also was tested and caught the most flies. Traps with greater entry areas, found in mesh traps, caught more flies than traps with smaller entry areas. In terms of sensitivity and selectivity, traps that caught more flies likewise caught flies earlier, and all traps caught 26–31% D. suzukii out of the total Drosophila captured. Future trap improvements should incorporate more entry points and focus on selective baits to improve efficiency and selectivity with regard to the seasonal behavior of D. suzukii.

Chemical Control Programs for Drosophila suzukii that Comply With International Limitations on Pesticide Residues for Exported Sweet Cherries

The recent introduction of Drosophila suzukii (Matsumura) into regions of the western United States that produce cherries, Prunus avium (L.), has resulted in the need for insecticide-based management programs close to harvest. These treatments have become problematic because of inconsistencies among export markets regarding maximum residue limits (MRLs) that are allowed for different insecticides on imported fruit. As a result, fruit that was treated and harvested in a safe manner according to the U.S. label issued by the Environmental Protection Agency may or may not qualify for export to countries that have MRLs that are lower than those of the United States, or where MRLs have not yet been established. This project addresses this issue by measuring the degradation curves of six insecticides when applied at 7 or 21 d before the initiation of harvest. Based on the results of these tests, we propose a selection of insecticides that can be used for spotted wing drosophila control, with the number of applications and sequence of insecticides used dependent on pest pressure and the number of days required between application and harvest. Three insecticides with favorable characteristics include lambda-cyhalothrin, spinosad and malathion, which allow producers to incorporate the principles of efficacy, fruit susceptibility, and resistance management and still allows for the export of fruit to all major export markets.

Trap Designs for Monitoring Drosophila suzukii (Diptera: Drosophilidae)

ABSTRACT Drosophila suzukii (Matsumura), an invasive pest of small and stone fruits, has been recently detected in 39 states of the United States, Canada, Mexico, and Europe. This pest attacks ripening fruit, causing economic losses including increased management costs and crop rejection. Ongoing research aims to improve the efficacy of monitoring traps. Studies were conducted to evaluate howphysical trap features affect captures of D. suzukii.We evaluated five colors, two bait surface areas, and a top and side position for the fly entry point. Studies were conducted at 16 sites spanning seven states and provinces of North America and nine crop types. Apple cider vinegar was the standard bait in all trap types. In the overall analysis, yellow-colored traps caught significantly more flies than clear, white, and black traps; and red traps caught more than clear traps. Results by color may be influenced by crop type. Overall, the trap with a greater bait surface area caught slightly more D. suzukii than the trap with smaller area (90 vs. 40cm2). Overall, the two traps with a side-mesh entry, with or without a protective rain tent, caught more D. suzukii than the trap with a top-mesh entry and tent.

Hot-Water Treatments for Control of Planococcus ficus (Homoptera: Pseudococcidae) on Dormant Grape Cuttings

Abstract Hot-water immersions were tested for control of mealybug Planococcus ficus (Signoret), on dormant grape cuttings used for nursery stock. A range of hot-water temperatures (47–58°C) were evaluated at immersion periods of 2, 5, 10, or 20 min, by using a total of 353,720 mealybugs across all treatments. A 5-min immersion at 51°C is effective in killing >99% of P. ficus. At or above this immersion period and temperature, there was no difference in mealybug stage mortality. We evaluated a commercial operation, which used a 5-min immersion in each of three water tanks: preheating (30.0 ± 3°C), hot-water (52.8 ± 0.3°C), and cooling (23 ± 3°C). The commercial procedure provided 99.8–100% mealybug control in each of three separate trials.

Southern Highbush Blueberries are A New Host for Scirtothrips citri (Thysanoptera: Thripidae) In California

Citrus thrips, Scirtothrips citri (Moulton), is a major pest for citrus growers in California (Flint et al. 1991; Morse 1995). Citrus thrips feed on the rind at the stem end of young citrus fruit causing a characteristic ring scar (Morse 1995; GraftonCardwell et al. 1998, 2003). They also feed on the new flush of citrus, causing twisting and abnormal growth (Grafton-Cardwell et al. 1998). Heavy infestations of citrus thrips cause new flush to die and drop from the plant (Grafton-Cardwell et al. 1998). Even though citrus thrips was first described based on the damage it caused on California citrus (Horton 1918), it was obviously present prior to the introduction of citrus in the region, i.e., it is native to California and northwestern Mexico and has been observed on over 50 host plants in California, in particular in association with plants that produce an aromatic oil (Morse 1995). Prior to 1992, highbush blueberries ( Vaccinium corymbosum L.) were not grown commercially in California due to the warm climate (Jimenez et al. 2005; Strik & Yarborough 2005). However, several southern highbush blueberry varieties were developed by crossing northern highbush blueberries with several other Vaccinium species (Jimenez et al. 2005; Strik & Yarborough 2005). Southern highbush blueberries require lower chill hours for bud break and are well adapted to California’s climate (Jimenez et al. 2005). As a consequence, California blueberry acreage dramatically increased after 1992 (Jimenez et al. 2005). In 2005, several growers reported widespread damage to the young foliage of their blueberries that appeared to be associated with thrips. Most of the damage was curling and abnormal growth of the new leaves as well as scarring of new twigs.

Seasonal phenology of Ferrisia gilli (Hemiptera: Pseudococcidae) in commercial pistachios.

ABSTRACT The mealybug Ferrisia gilli Gullan is a serious new pest of pistachios in California. It was first found near the town of Tulare in the late 1990s and has since spread to orchards in most pistachio-producing regions of the state. The seasonal phenology of F. gilli was evaluated in a commercial pistachio orchard in Tulare County during 2005 and 2006. During both seasons F. gilli overwintered as small nymphs and had three complete generations per year. Mealybug population densities were low and remained as immatures in March and April; by late May adult females formed and averaged (±SE) 1.3 ± 0.3 and 1.2 ± 0.3 per 0.75 m of sample branch in 2005 and 2006, respectively. The first in-season generation occurred from early June through mid-July, with mealybug densities ranging from 17.6 ± 5.6-26.4 ± 6.2 mealybugs per 0.75 m sample branch. The second in-season generation occurred from late July through September and had peak densities of 408.6 ± 93.9 and 182.0 ± 34.2 mealybugs per branch. In March and April mealybugs were located primarily on the buds and branch wood; in May the population was on branch wood as well as the rachis; from June through September the population was located primarily in the pistachio cluster. F. gillis seasonal phenology described herein was used to develop a management program.

Captures of Wild Ceratitis capitata, Bactrocera dorsalis, and Bactrocera cucurbitae (Diptera: Tephritidae) in Traps with Improved Multilure TMR Dispensers Weathered in California

Abstract During 2012–2013, solid Mallet TMR (trimedlure [TML], methyl eugenol [ME], raspberry ketone [RK]) wafers impregnated with DDVP (2, 2-dichlorovinyl dimethyl phosphate) insecticide were weathered during summer (8 wk) and winter (12 wk) in five California citrus-growing counties (Kern, Ventura, Orange, Tulare, and Riverside). In addition, TMR wafers without DDVP and with a Hercon Vaportape II insecticidal strip were compared with TMR dispensers with DDVP at Exeter and Riverside. Weathered treatments were shipped every week (overnight delivery) to Hawaii and frozen for a later bioassay in a 1,335-ha coffee plantation near Numila, Kauai Island, HI, where Mediterranean fruit fly, Ceratitis capitata (Wiedemann), oriental fruit fly, Bactrocera dorsalis Hendel, and melon fly, Bactrocera cucurbitae Coquillett, were all present. We compared trap captures of the three species, C. capitata, B. dorsalis, and B. cucurbitae, for the five different weathering locations. Captures of C. capitata, B. dorsalis, and B. cucurbitae with Mallet TMR dispensers (with DDVP) were not significantly different for the five locations. Captures with the Mallet TMR dispenser without DDVP and Vaportape were similar to those for Mallet TMR with DDVP, although there were some slight location differences. In conclusion, based on these results, the Mallet TMR dispenser could potentially be used in California habitats where large numbers of detection traps are currently deployed. Use of Vaportape with dispensers would not require them to be registered with US Environmental Protection Agency (EPA). Dispensers for use as Male Annihilation Technique (MAT) devices will be tested further in Hawaii.

Evaluation of Beauveria bassiana for Management of Citrus Thrips (Thysanoptera: Thripidae) in California Blueberries

ABSTRACT Citrus thrips, Scirtothrips citri (Moulton), is a plant-feeding pest most widely recognized for causing damage to citrus and mango fruits. This insect has broadened its host range to become a significant pest of commercial blueberries grown in the San Joaquin Valley of California. We evaluated Beauveria bassiana (Balsamo) for control of citrus thrips in blueberries grown under two watering regimes (drip irrigation with and without overhead sprinklers) and using two fungal formulations (commercially available spores in suspension vs. colonized seed) over two sampling periods, that is, for two 3-d periods after treatment. We found significant differences in thrips densities as a function of water regime treatment and fungal formulation. Thrips levels were reduced significantly with both fungal treatments at 3 d after treatment, but at 6 d, only results with colonized seed differed from the control treatment. These data suggest entomopathogenic fungi might be useful for control of citrus thrips on blueberries in particular situations (in organic production or as a resistance management tool) but that traditional pesticides will likely remain the preferred management option.

Development of Management Programs for White Grubs in California Blueberries

During the past few years, white grubs have become recognized as a pest of southern highbush blueberries in California. White grubs feed on plant roots causing the plant to be stunted. In some cases, plant death has occurred when large grub populations attack newly planted fields. The predominant white grub species in California blueberries was identified as Cyclocephala longula. Research on flight characteristics determined that grubs are primarily in the third instar in April, pupate in May, and fly from mid-June through mid-July. Egg hatch begins in mid-July. Adult beetles begin flying about 30 min after dark and can be collected for a period of about 2 hours with black-light traps. Evaluation of control methods found that the entomopathogenic nematode Heterorhabditis bacteriophora and the insecticide imidacloprid can both provide control of the grub. Applications of Heterorhabditis bacteriophora on April 1 initially only provided 8.3% control, but resulted in secondary spread that led to an epizootic within the grub population. Applications of Heterorhabditis bacteriophora and imidacloprid in August resulted in 81.6 and 71.1% control, respectively, the following June.

Chemical Degradation of TMR Multilure Dispensers for Fruit Fly Detection Weathered Under California Climatic Conditions

Abstract Degradation models for multilure fruit fly trap dispensers were analyzed to determine their potential for use in large California detection programs. Solid three-component male lure TMR (trimedlure [TML], methyl eugenol [ME], raspberry ketone [RK]) dispensers impregnated with DDVP (2, 2-dichlorovinyl dimethyl phosphate) insecticide placed inside Jackson traps were weathered during summer (8 wk) and winter (12 wk) in five citrus-growing areas. Additionally, TMR wafers without DDVP, but with an insecticidal strip, were compared to TMR dispensers with DDVP. Weathered dispensers were sampled weekly and chemically analyzed. Percent loss of TML, the male lure for Ceratitis capitata (Wiedemann) Mediterranean fruit fly; ME, the male lure for Bactrocera dorsalis (Hendel), oriental fruit fly; RK, the male lure for Bactrocera cucurbitae (Coquillett), melon fly; and DDVP was measured. Based on regression analyses for the male lures, TML degraded the fastest followed by ME. Degradation of the more chemically stable RK was discontinuous, did not fit a regression model, but followed similar seasonal patterns. There were few location differences for all three male lures and DDVP. Dispensers degraded faster during summer than winter. An asymptotic regression model provided a good fit for % loss (ME, TML, and DDVP) for summer data. Degradation of DDVP in TMR dispensers was similar to degradation of DDVP in insecticidal strips. Based on these chemical analyses and prior bioassay results with wild flies, TMR dispensers could potentially be used in place of three individual male lure traps, reducing costs of fruit fly survey programs. Use of an insecticidal tape would not require TMR dispensers without DDVP to be registered with US-EPA.