title: Lethal and Sublethal Effects of Insecticides on the Biological Attributes of Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae): a Biocontrol Agent of Parthenium hysterophorus L.
abstract: Acute toxicity and sublethal effects of six commonly used insecticides, i.e., malathion, carbaryl, imidacloprid, cypermethrin, dimethoate, and monocrotophos, were evaluated through biological and life table parameters of Zygogramma bicolorata Pallister in laboratory. Concentration of these insecticides was within the minimum ranges of recommended field rate. Among the insecticides tested for acute toxicity, monocrotophos and imidacloprid caused the highest mortality of third instars and prolonged the development time of treated larvae. Fecundity and egg viability were also reduced in monocrotophos-treated group. Sublethal toxicity (carryover effect) of insecticides was evaluated through life table analysis of F1progenies developed from surviving third instars treated for acute toxicity experiment. Survivorship was prolonged to 117 days in carbaryl treated group. Monocrotophos prolonged the overall immature development time compared to other insecticidal treatments and untreated control. Moreover, the lowest female survival, and the lowest value of life indices parameters, i.e., mx, R0, rm, and λ, was evident in monocrotophos-exposed groups compared to that in other tested insecticides. However, mean generation time (Tc) and doubling time (DT) were significantly prolonged in the insecticide-treated groups compared to those in the untreated group. A significantly greater number of females were produced in control groups than those in treated with malathion and sex ratio (proportion of male) was computed as 0.34 and 0.37, respectively. Based on the present study, it can be concluded that none of the tested insecticides can be classified as safe to Z. bicolorata. However, comparisons among the tested insecticides showed that malathion was less toxic compared to other insecticides tested.
authors.affiliation: Dept of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim Univ, Aligarh, 202002, India. fazilento10@gmail.com.|Glocal School of Agricultural Sciences, Glocal University, Saharanpur, India. fazilento10@gmail.com.|Division of Entomology, ICAR-Indian Agricultural Research Institute, New-Delhi, India. fazilento10@gmail.com.
authors.forename: F
authors.initials: F
authors.lastname: Hasan
authors.affiliation: Dept of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim Univ, Aligarh, 202002, India.
authors.forename: M S
authors.initials: MS
authors.lastname: Ansari
mesh_terms: D000818:Animals; D019659:Asteraceae; D061046:Biological Control Agents; D001517:Coleoptera / Q000187:drug effects*; D005260:Female; D005298:Fertility; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D008297:Male; D012744:Sex Ratio; D018675:Toxicity Tests
chemical_list: D061046:Biological Control Agents; D007306:Insecticides
keywords: Insecticides, biology, development, life table, sex ratio