Annual Report of The Kansai Plant Protection Society

In Nara Prefecture, spring occurrence of bud damage by the strawberry blossom weevil, Anthonomus bisignifer Schenkling, on forced strawberry and wild host plants were investigated. Overwintering adults emerged from hibernation in late March to early April and began to injure flower buds of Rubus hirsutus Thunb. About 2 weeks later, adults injured strawberry flower buds in a greenhouse from early to mid-April. Thereafter until late April, adults began to injure flower buds of Rosa multiflora Thunb. Overwintering adults used different wild host plants depending on the flower budding period. Larval occurrence was earlier on the greenhouse strawberry than on R. hirsutus growing outside of the greenhouse. The start of first generation adults' emergence from the pupae was estimated as about late April to early May. The density of damaged buds on the strawberry differed greatly among years for unknown reasons. Commercial concentrations of thiacloprid, spinosad, and malathion were effective against adults in in vitro experiments.

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An easy and reliable method for measuring ethylene production is a prerequisite for research on fungal ethylene biosynthesis. In the present study, Botrytis cinerea was used as a model fungus to develop a method to detect in vitro production of ethylene. Spore suspensions were cultured in methionine-supplemented PDA. Small plates were excised from the medium and placed in a sealed ampoule bottle for the ethylene production assay. Gaseous samples were obtained from the sealed bottle for gas chromatography analysis. Using this method, eight species of phytopathogenic fungi (Alternaria alternate, Aspergillus niger, B. cinerea, Cladosporium sp., Fusarium oxysporum, Rhizopus stolonifer, Pestalotiopsis spp. and Penicillium spp.) were shown to produce significant levels of ethylene. Ethylene production by these fungi varied markedly during the seven day incubation period. In addition to the facilitation of fungal ethylene analyses, the present method allowed the observation of morphological characteristics of the test fungi during the assay. This spore-plate method is a simple, convenient, and broadly applicable method for assessing fungal ethylene production in vitro. This method may improve screening of fungi with high ethylene production rates, analysis of fungal growth and development, and be useful in crop protection.

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We evaluated the curative and preventive effects of 15 fungicides on gray mold disease, Botrytis cinerea, by means of the spore inoculation method with cucumber cotyledons as test material and paper discs for inoculation. Treatment with iprodione, fludioxonil, azoxystrobin, and polyoxin provided a strong curative effect at 24 h after spore inoculation, but no fungicide was effective at 48 h after spore inoculation. Iprodione, fludioxonil, mepanipyrim, fenhexamid, boscalid, penthiopyrad, and azoxystrobin produced a strong preventative effect in a spore inoculation experiment at 21 d after fungicide application. We also performed a greenhouse experiment and confirmed that fludioxonil, boscalid, and a mixture of iminoctadine albesilate and fenhexamid were effective against gray mold disease on tomato plants for 21 d. The efficacy of these fungicides in controlling gray mold disease on strawberry plants was then confirmed in a farmer's greenhouse. Our study demonstrates that gray mold disease must be controlled by preventive spraying with fungicides that have a long residual control effect, treatment with fungicide after infection has already occurred is unlikely to be successful.

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Effect of foaming application of insecticides on insect pests of cabbage and eggplant was investigated in a field in Osaka Prefecture. With the foaming application of acetamiprid, the densities of green peach aphid, Myzus persicae (Sulzer), turnip aphid, Lipaphis erysimi (Kaltenbach) and common white, Pieris rapae crucivora Boisduval larvae on cabbage were effectively reduced, and the effect was equal with the spraying application of the insecticide. With the foaming application of cypermethrin, the density of P. rapae crucivora larvae on cabbage was effectively reduced, but the effect was lower than the spraying application of the insecticide. With the foaming application of acetamiprid, the density of cotton aphid, Aphis gossypii Glover on eggplant was effectively reduced, and the effect was equal with the spraying application of the insecticide. The results suggest that the foaming application of insecticide shows good control against insect pests on vegetables.

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