Flutuação populacional e distribuição vertical de Brevicoryne brassicae (L.) (Hemiptera: Aphididae) em couve

Abstract

RESUMOO conhecimento da dinâmica populacional e da distribuição vertical de insetos pragas em plantas hospedeiras é fundamental para o desenvolvimento de programas de manejo integrado de pragas. No presente trabalho efetuou-se um levantamento populacional de formas ápteras do pulgão Brevicoryne brassicae (L.), visando determinar a época de maior densidade populacional e a distribuição vertical em plantas de couve, (Brassica oleracea L. var. acephala DC.), cultivadas em Jaboticabal, SP. O estudo foi realizado durante as safras de brássicas de 1998 e 1999, efetuando-se correção da acidez do solo por meio de aplicação de calcário apenas no campo utilizado em 1998. A amostragem dos pulgões foi feita visualmente em folhas classificadas em três categorias: apical, mediana e basal. Nas duas safras estudadas, a infestação de B. brassicae na couve atingiu a maior densidade populacional em setembro, diminuindo rapidamente a seguir. Nos dois campos não se observou a mesma distribuição de B. brassicae em folhas apicais, medianas e basais. Os fatores que podem ter contribuído para as diferenças observadas no padrão de distribuição do pulgão devem estar relacionados com a precipitação pluvial e o calcário magnesiano.Palavras-chave: Insecta, pulgão, calcário, Brassica oleracea. ABSTRACT POPULATIONAL FLUCTUATION AND VERTICAL (WITHIN-PLANT) DISTRIBUTION OF BREVICORYNE BRASSICAE (L.) (HEMIPTERA: APHIDIDAE) ON KALEThe knowledge of the population dynamics and vertical distribution of insect pests in host plants are fundamental for the development of programs of integrated pest management. In the present work, a population survey of apterous cabbage aphid, Brevicoryne brassicae (L.), was carried out aiming to determine the period when this aphid reachs the highest population density and the within-plant distributions on its common host, kale, Brassica oleracea L. var. acephala DC., cultivated in Jaboticabal, State of São Paulo. The study took place during the 1998 and 1999 Brassica seasons, and limestone treatment was only made in the field cultivated in 1998. The cabbage aphid was sampled by visual search on leaves classified in three categories: top, middle and basal. In the two studied seasons, the B. brassicae infestations reached the highest population density in September, decreasing quickly afterwards. In the two fields, the same distributions of B. brassicae was not observed on top, middle and basal leaves. The factors that might have contributed to the differences observed in that distribution pattern were rainfall and magnesium limestone.

Within-Plant Distribution of Cotton Aphid (Hemiptera: Aphididae), in Cotton with Colored Fibers and Cotton-Fennel Intercropping System

“…The spatial distribution of insects is one of their most characteristic ecological features (Taylor 1984). Thus, elucidation of the population dynamics and vertical distribution of insect pests and their natural enemies on host plants is fundamental to the development of Integrated Pest Management programs (Cividanes and Santos 2003).…”

Within-plant distribution of cotton aphid (Hemiptera: Aphididae) in cotton cultivars with colored fibers

“…These factors consequently affect patterns of vertical distribution of apterous and alate aphids in the plants. The effects of these physiological factors on aphids depend on the plant's age, with a different behavior over the course of the plant's development (Cividanes and Santos 2003). The interactions observed between cotton cultivars and plant age, between plant region and plant age, and between cultivars and plant region regarding to the distribution of apterous or alate aphids on the plants may also be explained by factors such as leaf size, the number of nodes per stem, the number of leaves, the leaves' age, and the relative concentration of amino acids in the plant.…”

“…In terms of the peak occurrences of alate or apterous aphids, the highest proportions of apterous or alate aphids were found on nodes in the bottom region of the cotton plant, except in the BRS Rubí cultivar, where the proportionally highest occurrence of alate aphids was observed in the Leite et al (2007), who found more apterous individuals of A. gossypii in the bottom region of the plant than in the middle and top regions by studying okra crops (Abelmoschus esculentus (Linnaeus)). On the other hand, Cividanes and Santos (2003), who studied apterous aphids of the species Brevicoryne brassicae (Linnaeus) in cauliflower plants, found the highest proportion on the leaves of the middle region of the plants and the lowest proportion on the leaves of the top region of the plants. According to Gonzaga et al (1991), the distribution of A. gossypii in 93-day-old cotton plants grown in field conditions is weighted towards the top region of the plant rather than the middle and bottom regions.…”

“…Population fluctuation patterns for an aphid species may also differ among geographic regions, among different populations that have developed in the same region for some years, and among neighboring populations that have developed simultaneously (Cividanes and Santos 2003).…”

Dinâmica e distribuição espacial de diferentes espécies de pulgões e inimigos naturais em consórcio de erva-doce com algodão de fibra colorida

“…O consórcio do algodão com cultura aromática condimentar é vantajoso tanto para o produtor quanto para os comerciantes do Nordeste do Brasil, pois aumenta a renda familiar com a produção significativa ao longo do ano (LIMA et al, 2009). Além disto, o sistema de cultivo consorciado contribui para diversidade de inimigos naturais, reduzindo de forma significativa às populações de insetos sugadores BARBOSA, 2001;YAMAMOTO, 2002;MA et al, 2007;RAMALHO et al, 2012a).…”