Pathological Alterations in Embryos of the Codling Moth (Lepidoptera: Tortricidae) Induced by Methyl Bromide

Publisher： Entomological Society of America

ISSN： 1938-2901

Source： Annals of the Entomological Society of America, Vol.83, Iss.1, 1990-01, pp. : 59-67

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Abstract

Effects of methyl bromide applied as a fumigant to the eggs of the codling moth, Cydia pomonella (L.), were assessed using light microscopy and transmission electron microscopy. Cell division stopped within 1 h in nearly all embryos after application of a lethal dose (48 g/m³ for 2 h). A small number of terata were produced, the percentage increasing somewhat at a lower dose of fumigant. Cells in terata induced at early germ band stages showed the general characteristics of neoplastic cells. The severity of initial toxic effects of lethal-dose treatment on early embryonic tissue varied among the embryos and occasionally among cells in individual embryos. Methyl bromide is a general cellular toxin as expected from its action as a methylating agent with little substrate specificity. A lethal dose of methyl bromide generally led to some degree of transient cell swelling followed by severe disruption of the cytoplasm and plasma membrane, and to clumping of nuclear chromatin, followed by contraction, coagulation necrosis, and cell lysis.