Fatores que influenciam o ataque de mosca-branca em jiloeiro

Abstract

Resumo Este trabalho objetivou determinar os efeitos de pluviosidade e temperatura, predadores e parasitóides, dossel e idade das plantas, tipos e densidades de tricomas foliares, compostos químicos foliares, níveis de N e de K foliares, sobre a intensidade de ataque de moscabranca Bemisia tabaci (Hemiptera: Aleyrodidae) em jiloeiro Solanum gilo var. Gigante Portuguesa . As densidades de ninfas e de adultos de B. tabaci foram maiores nas folhas baixeiras do que nas apicais das plantas de jiloeiro. Com o aumento da temperatura do ar, observou-se incremento na densidade de adultos de B. tabaci nas folhas de jiloeiro.Termos para indexação: Solanum gilo, Bemisia tabaci, aleloquímicos, efeito climático, nitrogênio, potássio. Factors affecting attack rate of the whitefly on Solanum giloAbstract The objective of this study was to determine the effect of rainfall and temperature, predators and parasitoids, height within the canopy and plant age, chemical composition of leaves, levels of nitrogen and potassium in leaves and density of trichomes in leaves, on attack intensity of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) on Solanum gilo var. Portuguese giant . Densities of nymphs and of adults of B. tabaci were higher on leaves of the lower part than on those of the apical parts of plants of S. gilo. The number of adults of B. tabaci on leaves of S. gilo increased with temperature.

Factors affecting attack rate of whitefly on the eggplant

“…The negative correlation between nymphs and adults of whitefly densities and eggplant production observed in this study (y = 4.27 0.02x, R 2 = 0.93* and y = 4.33 0.06x, R 2 = 0.89*, respectively) is in agreement with other literature report for tomato (Schuster et al, 1995;Leite, 2000). A higher nymph and whitefly/leaf adults density was recorded at the base (104.68 and 33.56, respectively) and medium (87.56 and 21.62, respectively) and were statistically different as compared to the apex of the plant (4.74 and 3.12, respectively).…”

“…Such information could help the prediction of the attack by insects which in turn could reduce economic losses (Dent, 1995). Many factors can influence population density of whitefly in host plants such as weather, levels of N and K, age and vigor of plants, type and density of trichomes, allelochemicals and natural enemies (Horowitz et al, 1984;Horowitz, 1986;Hirano et al, 1993Hirano et al, , 1995Dent, 1995;Leite, 2000). The objective of this study was to determine the effects of weather, predators and parasitoids, canopy height and plant age, leaf chemical composition, levels of N and K and leaf trichomes on the intensity of Bemisia tabaci attack in Solanum melongena.…”

“…The preparation of slides and counting of trichomes were made by Leite (2000). Level of N and K in leaves of the eggplant was determined monthly in laboratory in one expanded leaf from the upper part of each of 10 plants/replication.…”

“…Bemisia tabaci lays its eggs on the younger leaves, which are often found at the apical part of the plants (Liu & Stansly, 1995). The second instar nymphs apparently do not move much and since the plant continues to grow, the adults emerge on the inferior third of the tomato plant (Liu & Stansly, 1995;Leite, 2000).…”

Factors affecting the attack rate of Bemisia tabaci on cucumber

“…Many factors can influence population density of whitefly in host plants such as weather, levels of nitrogen (N) and potassium (K), age and vigour of plants, type and densities of trichomes, allelochemicals and natural enemies (Dent, 1995;Leite, 2000).…”