200 Turner and Buss: Biology and Management of Allokermes kingii on Oak Very few natural enemies were found attacking any of the A. kingii life stages. Generalist predators included ladybird beetles (Chilocorus cacti (L.), Harmonia axyridis (Pallas)), green lacewings (Chrysoperla sp.), and predatory caterpillars (Holcocera coccivorella (Chambers), Euclemensia bassettella (Clemens), Laetilia spp., and Pyroderces sp.). The only parasitoid recovered was Metaphycus sp. Ants (Pheidole dentata (Mayr)) tended A. kingii and were observed foraging on the scale honeydew. Insecticide Study From the beginning to the end of the applications on 1 and 2 May 2003, the air temperature ranged from 26°C to 34.2°C (78.8°F to 93.6°F), relative humidity ranged from 76% to 100%, and wind speed ranged from 1.2 to 4.3 kph (0.7 to 2.7 mph). Cloud conditions ranged from partly cloudy to overcast. About 1.3 cm (0.5 in.) of rain fell lightly for 15 min after the horticultural oil, acephate, and oil plus acephate applications on 1 May 2003. The imidacloprid soil drench was applied after the rain. The foliar bifenthrin spray was applied on 2 May because the wind speed increased to >4 kph (2.5 mph) on 1 May. None of the insecticides tested provided consistent and satisfactory (>80% mortality) control of A. kingii nymphs (Table 1). Between 17% and 38% of the nymphs examined were dead within 1 week after treatment, but that number did not dramatically increase over time. Statistically more nymphs were dead from the acephate (33%) and horticul- tural oil (27%) treatments 3 WAT, compared to the control. However, the most mortality occurred 5 WAT, when nearly 42% of the nymphs were dead from the combined acephate and oil treatment. 9 May Treatment Rate Control — Acephate Bifenthrin 226.8 g/378 L (8 oz/100 gal) 2.3 L/378 L (0.63 gal/100 gal) Horticultural oil 7.6 L/378 L Imidacloprid (2.0 gal/100 gal) 5.7 g/7.56 L (0.2 oz/2.0 gal) Oil + acephate 7.6 L oil + 226.8 g 23.6 ± 10.7 13.2 ± 8.9 acephate/378 L (2.0 gal + 8 oz/100gal) F = 2.33 df = 5, 24 P = 0.07 ©2005 International Society of Arboriculture F = 3.89 df = 5, 24 P = 0.01 F = 2.62 df = 5, 24 P = 0.05 F = 0.70 df = 5, 24 P = 0.63 *Means within a column followed by an asterisk are significantly different from the control (Dunnett’s test) at P < 0.05. 41.7 ± 19.3* 15.5 ± 12.5 11.3 ± 5.7 (1 WAT) 5.7 ± 3.8 31.7 ± 4.1 24.7 ± 2.6 22 May (3 WAT) 0 16.0 ± 6.7 Nymphal survival decreased considerably in all of the treatments 1 WAT, compared to the pretreatment sample (Table 2). However, there were no differences among treatments, and the number of healthy nymphs on control trees also declined over time. Significantly fewer nymphs survived 3 WAT on trees treated with combined horticul- tural oil and acephate, compared to the control. The number of healthy nymphs increased on trees treated with acephate or bifenthrin 5 WAT and significantly so on bifenthrin 7 WAT, compared to the control. The population increase on 19 June 2003 in the bifenthrin treatment was largely from the crawler emergence from two female A. kingii. No other crawler emergence was noted from any other treatments or dates during the test. Table 1. Mean (±SEM) percentage of dead first and second instar Allokermes kingii per four-branch sample. 5 June (5 WAT) 0 19 June (7 WAT) 32.7 ± 5.2* 11.0 ± 3.2 12.0 ± 5.1 12.3 ± 5.7 18.3 ± 6.6 37.7 ± 11.1 26.7 ± 9.0* 15.8 ± 3.0 17.3 ± 5.8 DISCUSSION Allokermes kingii has one generation a year throughout most of its North American range (Hamon et al. 1976), but it is now known to have two generations a year in Florida. In Virginia, females lay eggs (1,390 to 5,789 eggs per female) from July to August, eggs hatch from September to Novem- ber, and the first instars are dormant until April. Then both female and male nymphs molt and migrate farther onto branches or the base of tree stems, respectively. Adults are present by mid-June in Virginia. The life cycle is more complex in Florida, with live adults present from April to December, first instars present from May to July and again from September to February, and second instars from July to September and October to April. The more rapid develop- ment of A. kingii in Florida is likely due to the warmer climate, longer growing season, and multiple-flushing growth habits of Q. geminata and Q. virginiana. Hosts include Q. borealis (L.), Q. coccinea (Muenchhausen), Q. ilicifolia (Wagenheimd), Q. imbricaria (Michaux), Q. laurifolia (Michaux), Q. phellos (L.), Q. rubra (L.), and Q. velutina (Lamarck) (Kosztarab 1996), and now also Q. geminata and Q. virginiana. 9.7 ± 2.7 20.1 ± 6.5 21.7 ± 9.2 24.2 ± 3.6 An integrated pest management program has not yet been established for A. kingii. Its natural enemy complex does not appear to adequately suppress populations, and environmental factors contributing to its
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