~ 354 ~ Journal of Pharmacognosy and Phytochemistry 2017; 6(3): 354-358 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2017; 6(3): 354-358 Received: 28-03-2017 Accepted: 29-04-2017 Bontha Rajasekar Department of Agril. Entomology, University of Agricultural Sciences‚ Dharwad, Karnataka, India Mallapur CP Department of Agril. Entomology, University of Agricultural Sciences‚ Dharwad, Karnataka, India Correspondence Bontha Rajasekar Department of Agril. Entomology, University of Agricultural Sciences‚ Dharwad, Karnataka, India Compatibility of Profenofos with selected agro- chemicals on Bt cotton Bontha Rajasekar and Mallapur CP Abstract Experiments were conducted to assess the emulsion stability revealed that out of four chemicals tested namely, carbendazim, copper oxychloride, NAA, and MgSO4 with profenofos 50 EC at 2 ml litre -1 , none of these products produced creaming matter or sediment, more than 2.0 ml at the top or bottom of the 100 ml cylinder. The results confirmed physical stability of these agro-chemicals with profenofos 50 EC. A field trial was conducted to evaluate the bioefficacy of combinations of profenofos 50 EC with selected Agro-chemicals, as foliar application on 90 days old Bt cotton against sucking pests and foliar diseases. The lowest mean population of aphids (5.87 3 leaves -1 ), leafhoppers (6.78 3 leaves -1 ), thrips (6.44 3 leaves -1 ), whiteflies (3.54 3 leaves -1 ) and mirid bugs (1.26 five squares -1 ) were recorded in profenofos 50 EC @ 2 ml + carbendazim 50WP @ 1.0 g with (47.70, 40.23, 64.95, 43.89 and 72.96) high % reduction over control, respectively. Treatments, profenofos in combination with carbendazim (36.30) and copper oxychloride (28.77) were recorded high % disease over control along with the alone fungicidal treatments against Alternaria blight and Bacterial blight, respectively. Profenofos in combination with carbendazim and copper oxychloride were found to be more effective in reducing the sucking pests population and foliar diseases incidence, but significantly reduced the natural enemies (coccinellids, chrysopids and spiders) in proving their harmfulness. All the tested treatments had not caused any phytotoxic symptoms on 90 days old Bt cotton crop. Keywords: Compatibility, combinations, profenofos, sucking pests, diseases and cotton 1. Introduction Cotton (Gossypium hirsutum L.), popularly known as “the white gold”, is an important commercial fibre crop grown under diverse agro-climatic conditions around the world. Introduction of second generation Bt cotton has given solution to the bollworm complex to the larger extent but at the same time they are susceptible to most of the sucking pests viz., aphid, leafhopper, thrips, whitefly and mirid bug, which occupied major pest status and contributed to lower yields. Apart from this, the diseases like Alternaria leaf spot and Bacterial blight are also posing threat to cotton cultivation. It requires large number of chemicals and sprays for managing different pests. 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 [1] . Incompatibility may cause loss of effectiveness, poor application and also phytotoxicity. Chemical incompatibility occurs when the material breaks down in to different compounds or when the products chemically combine to produce another, which involves deactivation and may result in complete or partial failure. Hence, knowledge on the chemical compatibility is necessary to be familiar with the efficacy of mixed chemicals in managing insect pest and diseases in field condition. In this background, experiments were designed to know the compatibility of a newer insecticide, profenofos 50 EC with other agro- chemicals against sucking pests, foliar diseases and natural enemies on Bt cotton. 2. Materials and Methods 2.1. Emulsion stability test Profenofos 50 EC was subjected to physical test for emulsion stability either alone or after mixing with fungicides or fertilizer or growth regulator such as carbendazim, copper oxychloride, NAA, and MgSO4. Emulsion stability test was carried out for profenofos alone and for the combination products as prescribed by Indian Standard specifications [2] . Standard hard water was prepared by dissolving 0.304 g anhydrous calcium chloride (CaCl2) and 0.139 g magnesium chloride (MgCl2) in one liter of distilled water. This solution had hardness equivalent of 342 ppm calcium carbonate and was used to prepare the insecticide test solutions. To such formulated insecticide suspension (30 ml), 30 ml of either of the proposed combination chemical (carbendazim or copper oxychloride or NAA or MgSO4) was added