Seletividade de agrotóxicos utilizados em pessegueiro sobre ovos e pupas do predador Chrysoperla externa

Abstract

Objetivou-se com este trabalho avaliar a seletividade de dezenove agrotóxicos utilizados na cultura do pessegueiro sobre ovos e pupas do predador Chrysoperla externa em condições laboratoriais (temperatura 25±1ºC, umidade relativa 70±10% e fotofase 14 horas). Os agrotóxicos foram pulverizados diretamente sobre ovos e pupas por meio de uma torre de Potter, utilizando a máxima dosagem recomendada para a cultura do pessegueiro. Foi avaliada a viabilidade de ovos e pupas, além da fecundidade e fertilidade de adultos emergidos de pupas tratadas. Os agrotóxicos foram classificados para ovos em função da redução na eclosão e, para pupas, em função do efeito total, conforme a escala de toxicidade proposta pela IOBC. A maioria dos agrotóxicos avaliados (8 inseticidas, 8 fungicidas e 2 herbicidas) se mostrou inócua (classe 1) a ovos e pupas, com redução na eclosão de larvas e efeito total em pupas inferiores a 30%. A exceção se deu para o inseticida óleo mineral, que reduziu a eclosão de larvas em 69,55% quando pulverizado em ovos e proporcionou efeito total em pupas de 36,22%, sendo classificado como levemente nocivo (classe 2) a ovos e pupas de C. externa

TOXICITY OF INSECTICIDES USED IN MUSKMELON ON FIRST-INSTAR LARVAE OF Chrysoperla genanigra FREITAS (NEUROPTERA: CHRYSOPIDAE)

“…According to Freitas and Morales (2009) Chrysoperla is one of the most important genus in the country, since from the 36 species of this genus, four were found in Brazil, and among these species is the C. genanigra, which was found only the muskmelon crops in the region of Mossoró RN. However, studies on selectivity to insecticides on C. genanigra are scarce and not yet published, and most studies on this genus are concentrated on the species C. externa (CASTILHOS et al, 2014) and C. carnea (MAIA et al, 2016). Thus, the conduction of research on C. genanigra, especially regarding the effect of phytosanitary products on different development stages of this insect, is essential for its conservation and introduction into agroecosystems.…”

Comparative Selectivity of Herbicides Used in Wheat Crop on the Predators Chrysoperla externa and Eriopis connexa

“…One week after the first laying, adults of C. externa were sexed and four samples of eggs deposited in a 24 hour interval were collected (Castilhos et al, 2014). The total number of eggs from each collection was measured and divided by the number of females in the cage in order to determine the average fecundity (number of eggs per female and day).…”

“…Thus, the use of selective pesticides is of paramount importance to delay or even avoid problems arising from their indiscriminate use. Selectivity is defined as the property that a pesticide presents to control a specific pest (weeds, insects, and diseases) with the least possible impact on its natural enemies in the agroecosystem under the same conditions in which the pest is controlled successfully (Castilhos et al, 2014).…”

Resistance Potential of <i>Chrysoperla carnea</i> (Stephens) to Insecticides Used Against Sucking Complex of Cotton

“…The larvae of C. carnea are generalist predator which can also feed on eggs and small larvae of lepidoptera, scales, aphids, psilids and whiteflies [5]. It is worth mentioning that the use of chrysopids in IPM as increased since last few years, Used Against Sucking Complex of Cotton mainly due to its adaptability, voracity and relative wide tolerance to several insecticides [6,7].…”

“…Theoretically, few studies have been addressed that all developmental stages (eggs, larva, pupa, and adult) of green lacewing are susceptible to insecticides, the exposure may lead to lethal and sub-lethal effects [7,12]. Most of the studies highlighted lethal and sub-lethal effects of selective insecticides on larvae and adult lacewing [13][14][15], and some have focused on eggs and pupae that can be considered more tolerant to insecticides [6,16,17].…”