Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Mais filtros

Base de dados
Intervalo de ano de publicação
J Econ Entomol ; 103(1): 119-26, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20214376


We conducted field trials at five different locations over a period of 6 yr to investigate the efficacy of imidacloprid applied each spring as a basal soil drench for protection against emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). Canopy thinning and emerald ash borer larval density were used to evaluate efficacy for 3-4 yr at each location while treatments continued. Test sites included small urban trees (5-15 cm diameter at breast height [dbh]), medium to large (15-65 cm dbh) trees at golf courses, and medium to large street trees. Annual basal drenches with imidacloprid gave complete protection of small ash trees for three years. At three sites where the size of trees ranged from 23 to 37 cm dbh, we successfully protected all ash trees beginning the test with <60% canopy thinning. Regression analysis of data from two sites reveals that tree size explains 46% of the variation in efficacy of imidacloprid drenches. The smallest trees (<30 cm dbh) remained in excellent condition for 3 yr, whereas most of the largest trees (>38 cm dbh) declined to a weakened state and undesirable appearance. The five-fold increase in trunk and branch surface area of ash trees as the tree dbh doubles may account for reduced efficacy on larger trees, and suggests a need to increase treatment rates for larger trees.

Besouros/efeitos dos fármacos , Fraxinus/parasitologia , Imidazóis/farmacologia , Inseticidas/farmacologia , Nitrocompostos/farmacologia , Solo , Animais , Controle de Insetos , Neonicotinoides
J Econ Entomol ; 94(6): 1378-85, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11777039


In this study, we addressed the question of whether or not native stands of blueberry (Vaccinium spp.) and/or huckleberry (Gaylussacia spp.) support populations of blueberry maggot, Rhagoletis mendax Curran, in the Great Lakes region. Infestation of commercial blueberries by the blueberry maggot, R. mendax, is a serious problem in many areas where blueberries are grown. In the past 10-20 yr, commercial bighbush blueberry, Vaccinium corymbosum L., production has expanded into places such as southern Ontario and southern Quebec where blueberry maggot had not previously been reported. In the mid-1990s, isolated infestations of commercial highbush blueberry were reported in southern Ontario. Because R. mendax was not considered endemic to that area, it was widely assumed that the pests had come into the fields via movement from exotic localities. Here we present an alternative hypothesis, that the blueberry maggots infesting newly established highbush plantations are derived from native blueberries growing in the vicinity. To test this hypothesis, in 1997-1999, we sampled potential native hosts for R. mendax (Vaccinium spp. and Gaylussacia spp.) from 31 localities in the Great Lakes region, primarily in Michigan and Ontario. R. mendax was reared from fruits of native hosts collected at four sites in Michigan and one site each in Ontario, Indiana, and Ohio. V. corymbosum was the predominant host infested, with infestation of this host observed at five of the seven sites. However, two huckleberry species [Gaylussacia baccata (Wangenheim) K. Koch, and Gaylussacia dumosa (Andersson) Torrey & Gray] had the highest rates of infestation that we observed (25.4 and 17.6%, respectively). These data represent the first published reports of R. mendax infesting native host plants in the Great Lakes region, and support the hypothesis that infestations observed in commercial fields may have originated from infested native host plants.

Mirtilos Azuis (Planta) , Dípteros , Huckleberry (Planta) , Animais , Great Lakes Region , Illinois , Indiana , Michigan , New York , Ontário
J Nematol ; 24(4S): 637-41, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19283039


Daily irrigated, 80% pan replacement, and nonirrigated field plots of Kentucky bluegrass (Poa pratensis L.) were inoculated with a mixture of Steinernema carpocapsae (All strain) and Heterorhabditis bacteriophora (HP-88 strain) in 1988. In 1989, daily irrigated and nonirrigated plots were inoculated with HP-88 alone. The turf and associated soil contained populations of Tylenchorhynchus dubius, T. nudus, Pratylenchus penetrans, Paratylenchus projectus, and Criconemella rustica. In irrigated plots in 1988, population densities of Tylenchorhynchus spp. were lower in plots inoculated with HP-88 plus All compared with that in control plots. The same effect was absent under nonirrigated conditions. In 1989, population densities of Pratylenchus penetrans associated with inoculated turf were lower than those recovered from noninoculated turf in irrigated but not under nonirrigated conditions. Population densities of plant-parasitic nematodes were generally higher in the irrigated compared with the nonirrigated environment.