Populational fluctuation of lace bug in cassava

Abstract

RESUMO:Vatiga illudens é uma praga de importância econô-mica para a cultura da mandioca. Conhecer a época de incidên-cia desse inseto em associação com fatores ambientais possibilita estratégias de controle. O objetivo deste trabalho foi determinar a flutuação populacional de V. illudens em cultivares de mandioca e verificar a correlação desses insetos com os fatores climáticos em Dourados, Mato Grosso do Sul. Foram avaliadas quatro cultivares de mandioca: Kiriris, N-25, IAC 90 e Fécula Branca. A avaliação populacional do percevejo-de-renda foi realizada durante 18 meses, observando 2 ciclos da cultura. Quinzenalmente, foram amostradas aleatoriamente quatro plantas centrais de cada parcela e cinco folhas do terço médio de cada planta, quantificando o número de ninfas e adultos por folha. Vinte meses após o plantio, foram colhidas duas fileiras centrais de mandioca de cada parcela e mensurada a produtividade em kg ha -1 . O delineamento experimental foi em blocos casualizados com quatro tratamentos e duas repetições. O pico populacional das ninfas e adultos para o primeiro ciclo da cultura ocorreu nos meses de março a maio. Para o segundo ciclo, esses índices populacionais aconteceram nos meses de janeiro a abril. O cultivar Kiriris apresentou maior número médio de ninfas e de adultos por folha de mandioca e o cultivar IAC 90, o menor número de insetos. Houve correlação negativa entre a população de insetos adultos e a produtividade de raízes. As temperaturas máximas, médias e mínimas afetaram a população de ninfas de V. illudens. Esses resultados são fundamentais para definir estratégias de manejo para controle do percevejo-de-renda. PALAVRAS-CHAVE: Vatiga illudens; Manihot esculenta; manejo integrado de pragas. ABSTRACT: Vatiga illudens is a pest of economic importancefor the cultivation of cassava. Knowing the time of incidence of this insect in combination with environmental factors enables control strategies. The objective of this study was to determine the population dynamics of V. illudens in cassava cultivars and the correlation of these insects for climatic factors in Dourados, Mato Grosso do Sul. Four cultivars of cassava were evaluated: Kiriris, N-25, IAC 90 and Fécula Branca. Population assessment of the lace bug was conducted over 18 months observing 2 crop cycles. Fortnightly, they were randomly sampled four central plants of each plot and five leaves from the middle third of each plant, quantifying the number of nymphs and adults per leaf. Twenty months after planting cassava, two central rows of each plot were harvested and measured productivity in kg ha -1 . The experimental design was randomized blocks with four treatments and two replications. The peak population of nymphs and adults for the first crop cycle occurred during the months from March to May. For the second cycle, these population indices happened in the months from January to April. Cultivar Kiriris showed the highest mean number of nymphs and adults per leaf cassava and cultivar IAC 90, the lowest number of insects. There was a neg...

Occurrence and distribution of lace bug, whitefly, and shoot fly pest species on cassava (Manihot esculenta) crops according to region in Paraná State, Brazil

“…Another study found that 39 % of root yields were decreased by pest damage (Bellotti et al, 1999). Recent studies have identified a negative correlation between the population of adult insects and root yield (Bellon et al, 2017).…”

“…These crops could be a unique income source for resource-poor families. In general, cassava pests develop properly in environmental conditions that are suitable for the related plants, particularly under higher temperatures (Waddill, 1977;Gisloti & Prado, 2013;Bellon et al, 2017;Miranda et al, 2009;Andrade et al, 2012), which generally occur in the Paraná regions in spring and summer.…”

“…N. perezi shows improved development under warming temperatures (Waddill, 1977) and has a life cycle of approximately 40 days (Gisloti & Prado, 2013). V. illudens populations are affected by temperature, but not by precipitation and relative humidity (Bellon et al, 2017). The biological life cycle of V. manihotae occurs over approximately 22 days (25 + 2 ℃) (Miranda, Rheinheimer, Bellon, Gazola, & Pietrowski, 2009).…”

Short Communication: First record of the cassava lace bug Vatiga illudens (Drake, 1922) (Hemiptera: Heteroptera: Tingidae) from East Java, Indonesia

“…Since a decade ago, V. illudens has been recognized as a devastating pest of cassava in the Neotropical Region, mainly in Brazil (Bellon et al 2017;da Silva Wengrat 2020). However, V. illudens infestation has been progressively increasing outside its native range.…”