Assessing toxicity of post-emergence herbicides to the Spilarctia obliqua Walker (Lepidoptera: Arctiidae)

Abstract

The lethal and sublethal eVects of three post-emergence herbicides, 2,4-D ethyl ester (Weedkill 80WP), imazethapyr (Pursuit 10EC) and quizalofop ethyl (Tergasuper 5EC) fortiWed with artiWcial diets were studied on larvae of Spilarctia obliqua Walker (Lepidoptera: Arctiidae). Quizalofop ethyl and imazethapyr caused signiWcant reduction of pest survival at almost all levels; however, 2,4-D ethyl ester was nontoxic. Interestingly, LC 50 data (0.230 and 0.855% for quizalofop ethyl and imazethapyr, respectively) obtained from probit analysis were almost equal to labeled doses (x) of quizalofop ethyl (x = 0.16%) and imazethapyr (x = 0.625%), which shows the high toxicity of these compounds against S. obliqua larvae. Among the three herbicides, imazethapyr caused sublethal eVects on this pest, increasing the larval period at almost all concentrations tested in the artiWcial diet. Considering the markedly signiWcant eVect of quizalofop ethyl on pest survivorship with no sublethal eVect, we suggest incorporating it into the integrated pest management module for S. obliqua in legumes or oilseed crops with other biorational insecticides. Based on toxicity, imazethapyr can be a potential candidate for integrated management of S. obliqua. However, because of its sublethal eVects, we advocate caution while using it in the presence of pest infestations.

Chemical composition, phytotoxic and antifungal activities of Pinus pinea essential oil

“…As per Agrow (2007) report, the total value of world's agrochemical market was between US$31 and US$35 billion and among the products, herbicides accounted for 48% followed by insecticides (25%) and fungicides (22%). However, the excessive use of synthetic pesticides in the croplands, urban environment, and water bodies to get rid of noxious pests has resulted in an increased risk of pesticide resistance, enhanced pest resurgence, and development of resistance/ cross-resistance, toxicological implications to human health, and increased environmental pollution (Gupta and Bhattacharya 2008;Hong et al 2009). Efforts are thus being made to replace these synthetic chemicals with alternatives which are safer and obviously less harmful to the environment (Zanie et al 2008;Seyran et al 2010;Yangui et al 2010).…”

First record of the entomopathogenic fungus Entomophaga aulicae on the Bihar hairy caterpillar Spilarctia obliqua in Manipur, India

“…In India it is a serious pest in Bihar, Madhya Pradesh, Uttar Pradesh, Punjab, Manipur, and other states. Due to its highly polyphagous nature, it attacks pulses, oilseeds, cereals, certain vegetables, mulberry, medicinal, aromatic and other economic plants, and causes severe economic damage (Gupta and Bhattacharya 2008). It is one of the major pests of mulberry, and can cause a total foliage loss up to 4.9% in mulberry plantations in Karnataka, India (Shree and Manjunatha 1998).…”

“…Caterpillars feed gregariously during the early (first to third instar) larval stages (Plate 1- Fig. 1) and solitarily in the late (fourth to fifth instar) larval stages (Gupta and Bhattacharya 2008). Chemical control of this pest is difficult and very high doses of pesticides are required.…”

Detrimental effect and GC-MS analysis of some plant oils against Polyphagous pests Spodoptera litura and Spilarctia obliqua

“…(Tandi and Narayananan, 2002 ;Qin et al, 2004;Babu et al, 2017;Kalyan and Ameta, 2017). During the early instars, the caterpillars feed gregariously on the leaves then disperse and cause severe economic damage (Gupta and Bhattacharya, 2008). Farmers use various synthetic insecticides for the management of these pests (Venkateshwarlu et al, 2006;Deshmukh et al, 2010).…”