Research Mini Abstracts

R. S. Cowles; M. E. Montgomery; C.A.S.-J. Cheah. 2006, vol. 99, no. 4, pp. 1258 - 1267 Activity and Residues of Imidacloprid Applied to Soil and Tree Trunks to Control Hemlock Woolly Adelgid in Forests
We studied imidacloprid application methods and timing to control the hemlock woolly adelgid in forests. The methods compared were 1) soil injection near the trunk; 2) soil injection dispersed throughout the area under the canopy; 3) soil drench near the base of the trunk; and trunk injection with the 4) Arborjet, 5) Wedgle, and 6) Mauget systems. Relative to the untreated control trees, all the soil applications resulted in population reductions, but none of the trunk injections resulted in reductions. Fall and spring treatment efficacy did not differ. Reductions by the soil treatments were between 50 and 100% (avg 80%) by the first fall and 83-100% (avg 98.5%) by the second fall. Analysis of imidacloprid residues found residues in sap, needles, and twigs 1 mo to 3-yr after application. A high degree of suppression of the adelgid on forest trees was associated with residues in hemlock tissue >120 ppb 2 yr after soil treatment. Although precise relationships between residues and efficacy are elusive, it is clear that soil application of imidacloprid resulted in chronic residues of imidacloprid in tissues and suppression of adelgid populations for >2 yr.

David H. Oi; Faith M. Oi. Journal of Economic Entomology. 2006, vol. 99, no. 5, pp. 1739 - 1748
Speed of Efficacy and Delayed Toxicity Characteristics of Fast-Acting Fire Ant (Hymenoptera: Formicidae) Baits
Efficacy and speed of action of fire ant baits that claim fast control of colonies were compared with a standard bait. More than 85% of red imported fire ant laboratory colonies provided bait containing the active ingredient indoxacarb died within 3 d, and all colonies were dead in 6 d. Standard bait containing hydramethylnon (eg. Amdro) resulted in death of 60% of the colonies in 9 d. Bait containing spinosad did not cause colony death. Under field conditions, one-half of the areas treated with the indoxacarb bait did not have any active fire ant nests within 3 d, whereas 11 d was needed to reach the same level of control with the hydramethylnon bait. Spinosad had a maximum of 17% of the treated areas without nests after 3 d. The delay in death of fire ant adults treated in the laboratory with the indoxacarb and spinosad baits was shorter than the standard hydramethylnon bait, which had mortality similar to the traditional delayed toxicity criterion. Indoxacarb caused mortality of 57% at 24 h and 100% at 48 h; however, visual symptoms of toxicity were not readily observed for at least 8 h before the abrupt increase in death. Spinosad caused 96% mortality by 24 h, and initial mortality became apparent at 4 h. Time required for death of 15% of a treated population (LT15) of spinosad, indoxacarb, and hydramethylnon was 3, 9, and 16 h, respectively. Delayed toxicity characteristics of the fast-acting indoxacarb bait may be useful for the development of other fast-acting ant baits.

Christopher J. Fettig et al. Journal of Economic Entomology. 2006, vol. 99, no. 5, pp. 1691 - 1698
Effectiveness of Bifenthrin (Onyx) and Carbaryl (Sevin SL) for Protecting Individual, High-Value Conifers from Bark Beetle Attack in the Western US
Trees, such as those located in residential, recreational, or administrative sites, are particularly susceptible to bark beetle attack as a result of increased amounts of stress associated with drought, soil compaction, mechanical injury, or vandalism. Tree losses in these unique environments generally have a substantial impact. In this study, authors assess the efficacy of bifenthrin (Onyx) and carbaryl (Sevin SL) for protecting various pines from various bark beetles. Sevin SL (2.0%) was effective for protecting P. ponderosa, P. contorta, and P. monophylla for two field seasons. Estimates of efficacy could not be made during the second field season in P. edulis and P. engelmannii due to insufficient mortality in untreated, baited control trees. Two field seasons of efficacy was demonstrated in P. ponderosa/D. brevicomis and P. monophylla for 0.06% Onyx. We conclude that Onyx is an effective individual tree protection tool, but repeated annual applications may be required in some systems if multiyear control is desired.

Punya Nachappa; L. P Guillebeau; S. K. Braman; J. N. All. 2006. J. Econ.Ent. 99(5): 1711-1716.
Susceptibility of Twolined Spittlebug (Hemiptera: Cercopidae) Life Stages to Entomophagous Arthropods in Turfgrass
The twolined spittlebug, is an economic pest of turfgrass in the southeastern United States. No data concerning natural enemies of P. bicincta in turfgrass have been reported previously. We compared predation of spittlebug eggs, nymphs, and adults in the laboratory by potential generalist predators commonly found in turfgrass: bigeyed bugs Geocoris uliginosus Say and Geocoris punctipes Say; red imported fire ant, Solenopsis invicta Buren; wolf spiders (Lycosa sp. Walckenaer); carabid beetles Harpalaus pensylvanicus DeGeer and Calosoma sayi Dejean; and tiger beetles Megacephala carolina carolina L.

Eggs were readily consumed by generalist predators. Fire ants consumed 100% of the eggs offered. Ground beetles were also significant predators of P. bicincta eggs. Nymphs live in spittlemasses that protect them from attack by predators, but exposed nymphs were susceptible to attack when removed from their spittlemasses. Fire ants and tiger beetles caused significant mortality of exposed nymphs. Fireants and tiger beetles killed 100% of the adult spittlebugs in laboratory bioassays. Lycosa spiders are less voracious predators of adults. Sound background knowledge about twolined spittlebugs and its potential natural enemy complex is important for the development and implementation of a detailed, site-specific, biologically based pest management program in turfgrass.

D.W. Held, P. Goniska, & D. Potter. 2003 Jour. Econ. Ent. Vol 96, No 1.
Evaluating Companion Planting and Non-host Masking Odors for Protecting Roses from the Japanese Beetle
Companion planting of certain herbs and use of mess bags did not reduce damage to rose foliage. Control plants had significantly less damage than the treatments.

Eric P. Benson, Patricia A. Zungoli, and Melissa B. Riley. 2003 Jour. Econ. Ent. Vol 96, No 1.
Effects of Contaminants on Bait Acceptance by Solenopsis invicta (Hymenoptera: Formicidae)
Three commonly used fire ant baits, Amdro, Ascend, and Maxforce, were exposed to potential, volatile contaminants. The contaminants included the insecticides Orthene Fire Ant Killer, Tempo 2, cigarette smoke, gasoline and others. These results indicate that volatile insecticides and products
can contaminate fire ant baits. Some insecticides and products, such as gasoline, can significantly affect bait palatability and may adversely impact control.

Y. Q. Tang, A. A. Weathersbee, III, and R. T. Mayer. 2002. Envir. Ent. Vol.31, No.1. p.172-176.
Effect of Neem Seed Extract on the Brown Citrus Aphid and its Parasitoid Lysiphlebus testaceipes (Hymenoptera:Aphidiidae) Spraying neem extract (11?180 ppm AZ) onto potted citrus plants in the greenhouse significantly reduced aphids 20?100%, while control aphid populations increased 950% 7 d after treatment. Application of the extract had little impact on the survival of adult parasitoids and developing parasitoids within aphids because parasite emergences were similar between treated and untreated parasitized aphids. These results indicate that neem extract may be compatible with integrated pest management programs in citrus and should be evaluated for field efficacy.

Ellis, Donna, Richard McAvoy et al. 2001. Florida Entomologist. Vol. 84. No. 2. p.215-221.--Evaluation of Serangium parcesetosusm (Coleoptera: Coccinellidae) for Biological Control of Bemesia argentifolii (Homoptera: Aleyrodidae) on Poinsettia
Contol of Silverleaf whitefly in greenhouse Poinsettia using biological control agents has been unreliable. This coccinellid shows great promise. Our data suggest that Serangium may work well in a multiple species biological control program on whiteflies on Poinsettia in greenhouses. However, further study is needed on interspecies interactions.

Christopher Asaro1 and C. Wayne Berisford. 2001. Envir. Ent. Vol. 38, No.4. pp 776-794
Predicting Infestation Levels of the Nantucket Pine Tip Moth (Lepidoptera:Tortricidae) Using Pheromone Traps
At six sites in the Georgia Piedmont, adult tip moths were monitored through one or more years using pheromone traps while population density and damage for each tip moth generation were determined. During most years, trap catch was higher during the first adult generation compared with subsequent generations regardless of population density. Within each generation, trap catch was moderately to highly correlated with associated population density or damage levels. The models presented herein should be used with caution because they are likely to be region-specific. Validation of these relationships is necessary before widespread application of these models is warranted.

Fungus Gnat Parsitoids in Greenhouse - from Biological Control News— Raymond A. Cloyd, Univ. of Illinois
http://www.entomology.wisc.edu/mbcn/kyf702.html
    Fungus gnats, Bradysia spp. are major insect pests in greenhouse crop production systems. The adults are a nuisance, and can carry spores of soil and foliar pathogens on their bodies. The larvae cause direct injury by feeding on plant roots, which reduces the plant’s ability to take-up water and nutrients. Also, the wounds created by larval feeding provide an entry site for secondary soil-borne pathogens. In addition, fungus gnat larvae have been shown to directly transmit soil-borne pathogens such as Pythium spp. to plants.
    Two very good biological control agents are commercially available for controlling fungus gnats.
These are the entomopathogenic nematode Steinernema feltiae and the soil-predatory mite
Hypoaspis miles. Both have proven effective in controlling fungus gnats in commercial greenhouse
production systems.
    Females insert eggs into fungus gnat larvae. They can develop in each of the three larval instars. S.pauperi is a solitary parasitoid, with only one parasitic wasp emerging from each fungus gnat pupa. The parasitized larvae live until pupation, then die, after which the wasp pupates. The parasitoid has a potential maximum rate of population increase that is higher than fungus gnats at 23°C; however, the parasitized fungus gnat larvae may still cause plant damage during the interval between parasitization and death. The parasitoid has been demonstrated to be a useful biological control agent of fungus gnats in Swedish greenhouses. At the University of Illinois Plant Sciences Conservatory, S. pauperi (identified on yellow sticky cards) has provided seasonal control of fungus gnats to the point that insecticides are generally not needed.

Iersel, Marc, R. Oetting, and D. Hall. 2000. J. Econ. Entomology (93) 813-819. Imidacloprid Applications by Subirrigation for Control of Silverleaf Whitefly on Poinsettia.

Different amounts of imidacloprid were applied by subirrigation to poinsettias in the greenhouse. Uptake was measured, as was whitefly infestation. All imidacloprid treatments resulted in a significant decrease in both the survival of adult whiteflies and number of immature whiteflies on the plants. Subirrigation treatments resulted in better control of adult and immature whiteflies than drench application. Withholding water for 2-4 days prior to application improved control of immature whiteflies. This indicates that the application of imidacloprid to poinsettia by subirrigation is a practical and efficient method to control silverleaf whiteflies.

Bell, Michelle & James R. Baker. 2000, J. Econ. Entomology 93(3):800-804. Comparison of Greenhouse Screening Materials for Excluding Whitefly and Thrips.

In 1996, Twenty-eight greenhouse screening materials were compared for air flow resistance, exclusion of silverleaf whitefly and exclusion of thrips. Those products with 90%+ efficacy for exclusion for either insect were: BugBed 123, No-Thrips, BugBed 110UV, Econonet S, BugBed 85, Econet T, Pak 52x52, and Protex. Others are listed.

Eliason, Eileen and Daniel Potter. 2000. J. Econ. Entomology 93(3):757-762. Dogwood Borer Infestation of Horned Oak Galls.

In Kentucky, woody stem galls on pin oak , Quercus palustris, formed by the gall wasp Callirhytis cornigera, were found to be infested by the Dogwood borer, Synanthedon scitula, as heavily as 12-15% in 2-3 year old stem galls.

Mannion, C., H. Winkler, et al. 2000. J. Econ. Entomology 93(1):48-53. Interaction Between Halofenozide and the Entomopathogenic Nematode Heterorhabditis marelatus for Control of Japanese Beetle Larvae.

Laboratory biossays were conducted using H.m.IN strain and halofenozide against both overwintered and nonoverwintered 3rd instars of Japanese beetle. Imidacloprid was used as a standard. Larval mortality was evaluated at 7, 14, and 21 days. Neither insecticide treatment surpassed 60% mortality, while both rates of nematodes resulted in 100% mortality.

J. T. Zenger and T. J. Gibb. 2001. J. Econ. Entomology. 94(1) Impact of Four Insecticides on Japanese Beetle Egg Predators and White Grubs in Turfgrass.

Field experiments were conducted to measure the effects of four commonly used turfgrass insecticides (isofenphos,
diazinon, imidacloprid, halofenozide) on white grubs (Coleoptera: Scarabaeidae) and ant predators of white grub eggs. Isofenphos and diazinon significantly reduced both ant numbers and white grub egg predation, whereas (Merit) and a single halofenozide (Mach 2) treatment did not significantly impact either measurement. A second halofenozide treatment significantly reduced white grub egg predation. Isofenphos and diazinon were ineffective at controlling Japanese beetle grubs when applied in June but were highly efficacious when applied in August. Evidence of enhanced biodegradation was found in plots that received both June and August applications of diazinon. Both June and August applications of imidacloprid and halofenozide provided good control of white grubs.

Eliason, E., & D. Potter. 2000. J. Econ. Entomol.93(1):165-171. Impact of Whole-Canopy and Systemic Insecticidal Treatments on Callirhytis cornigera (Hymenoptera:Cynipidae) and Associated Parasitoids on Pin Oak.

The gall wasp C.c. is a cynipid with alternating generations that produce large, woody stem galls and tiny blister-like leaf galls on pin oak, Quercus palustris. Three approaches at reducing galls were tested. First were sprays with bifenthrin or chlorpyrifos in late March. Second was concentrate solutions of abamectin, imidacloprid or bidrin injected into sapwood. Third was systemic acephate, abamectin, dimethoate, or imidacloprid sprayed at leaf expansion. Though some treatments affected gall inhabitants. Bifenthrin sprays at bud break provided the greatest reduction in new leaf galls. This study suggests that gall wasp outbreaks are unlikely to be controlled by a single treatment, regardless of application method.

Majeau, G., J. Brodeur & Y Carriere. 2000. J. Econ. Entomol.93(2): 368-373. Lawn Parameters Influencing Abundance and Distribution of the Hairy Chinch Bug (Hemiptera:Lygaeidae).

Management of lawns that promotes conditions detrimental to the development of insect pests may represent a valuable environmentally benign turfgrass management strategy. In the cool-humid region of Quebec, Canada, we investaged 45 lawns infested with hairy chinch bug, Blissusleucopterushirtus. Chinchbug population desnity was associated positively with abundance of periennial ryegrass. [snip] No significant relationship was found between thatch thickness and patterns of chinch bug abundance and distribution. These results suggest that management of lawns to respectively increase and decrease abundance of creeping bentgrass and perennial ryegrass could faciliate control of hairy chinch bug populations in cool-humid regions.

Wilson, M. J., L. A. Hughes, D. Jefferies and D. M. Glen. 1999. Slugs (Derocerasreticulatum and Arion ateragg) avoid soil treated with the rhabditid nematode Phasmarhabditishermaphrodita. Biological Control 16(2):170-176.

The parasitic nematode Phasmarhabditishermaphrodita occurs naturally in the UK, where it has been developed as a commercial control for slugs. Researchers in the UK found that pest slugs can detect the presence of and avoid soil treated with these nematodes. Slugs fed and rested preferentially on the untreated halves of boxes of soil during a 12-day period. One slug species tested avoided soil treated with 38 nematodes/cm2 -- which is similar to the recommended rate for field application --but was not repelled at lower nematode densities. Nematode movement in the soil in the boxes was minimal.

It may be possible to protect certain crops from slug damage by treating the area immediately around the sensitive plants with a narrow band of nematodes. This would deter slug feeding using far fewer nematodes than would be necessary for slug control by treating the entire soil surface. It is suggested this would be most effective for crops grown in widely spaced rows. Although the nematode is not currently commercially available in the U.S., efforts are being made to have it approved for commercial use here.