Physical and biological compatibility of diafenthiuron with micro/macro nutrients fungicides and biocontrol agents used in cardamom

Abstract

In the context of complex field problems, compatibility of an efficacious insecticide with other agrochemicals normally used in the field is essential. In this view diafenthiuron, a novel insecticide which inhibits ATP synthesis, used widely for pest management in cardamom, was tested for its compatibility with agrochemicals viz., fungicides and nutrients normally used in the crop. The results revealed that all the chemicals tested were physically and biologically compatible with diafenthiuron by means of physical stability and phytotoxicity ratings in the field. But the bioefficacy study on Conogethes punctiferalis in the laboratory and bioefficacy studies in the field against Sciothrips cardamomi reveal that diafenthiuron is incompatible and should not be sprayed along with fungicides like mancozeb and copper oxychloride. Another study on the compatibility of diafenthiuron with antagonistic microorganisms of plant pathogens viz., Trichoderma viride and Pseudomonas fluorescens revealed that diafenthiuron had some inhibitory effect on the mycelial growth of T. viride. Diafenthiuron did not affect the growth of P. fluorescens and thus can be used simultaneously for the control of insect pests and seed-and soil-borne diseases.

Compatibility of Diafenthiuron with Selected Agro-Chemicals on Bt Cotton

“…The results confirmed the physical stability of diafenthiuron 50 WP with selected agrochemicals. The findings of the present study are in agreement with the findings of Stanley et al (2010) opined that none of the chemicals tested viz., urea, borax, molybdenum, mancozeb, copper oxychloride and carbendazim in combination with diafenthiuron 50 WP at 1.6 g litre -1 , produced creaming matter or sediment, more than 2.0 ml at the top or bottom of the 100 ml measuring cylinder by means of physical emulsion stability test.…”

“…Results on the investigations conducted to find out the phytotoxic effects of these combination products on RCH-2 Bt cotton revealed that diafenthiuron 50 WP at @ 0.6 g litre -1 with the above agro-chemicals at recommended dose had not caused any phytotoxic symptoms such as injury to leaf tip and leaf surface, wilting, vein clearing, necrosis, epinasty and hyponasty on 90 days old cotton crop (Table 3). The results of present study are in line with the investigations of Stanley et al, (2010) revealed that diafenthiuron alone and its combinations with carbendazim, MgSO 4 and molybdenum did not cause any phototoxic symptoms such as injury to leaf tip and leaf surface, wilting, vein clearing, necrosis, epinasty and hyponasty in cardamom. It might be the first report in studying the compatibility of diafenthiuron 50 WP with selected agro-chemicals on Bt cotton in India.…”

“…It is often economical and convenient to apply a mixture of two or more pesticides and nutrients when a wide range of pests or maladies are to be managed at a time. This saves time, labour and cost which are the three major but scarce inputs in agricultural systems nowadays (Stanley et al, 2010). Incompatibility may cause loss of effectiveness, poor application and also phytotoxicity.…”

Toxicity of diafenthiuron to honey bees in laboratory, semi-field and field conditions

“…Diafenthiuron has been reported to be efficacious against cardamom pests. Diafenthiuron 500 g kg −1 WP at 1.6 g L −1 was found to be very effective in controlling C. punctiferalis , to the tune of about 90% after three sprays,21 and is used extensively in cardamom plantations of South India 5. Recommendation for the use of insecticides in IPM programmes has been made in the past on the basis of topical toxicity data, particularly by using selectivity ratios 22, 23.…”

“…In field conditions, it is photochemically transformed to 3‐(2,6‐di‐isopropyl‐4‐phenoxyphenyl)‐1‐ tert ‐butyl carbodiimide (DFCD), which is considered to be the agent responsible for the biological activity 3, 4. Diafenthiuron at 0.08% was found to be very effective against the cardamom borer, Conogethes punctiferalis Guenee, and also the thrips, Sciothrips cardamomi Ramk 5…”