Evaluation of seed dressing insecticides for the control of maize lethal necrosis vectors

Most of the overwhelming plant diseases caused by viruses including maize lethal necrosis (MLN) are attributed to viruses transmitted by vectors. The transmission of MLN from plant to plant by vectors provides the main means of spread in the field and that cause severe economic loss. Methods to control the vectors of plant virus diseases are intended at eliminating or altering one or more of the primary contributors (vector, virus, and host plant) in the transmission process or at preventing their coming together. The current experiments were conducted to evaluate seed-treatment insecticides for their efficacy on early season control of insect vectors of MLN causing viruses. The study on the effects of insecticide treatments on germination revealed that it does not significantly influence the germination of maize seed even up to 6 months storage before planting. Among the tested seed treatment insecticides, thiamethoxam 25% at 2.0 g/kg seed and imidacloprid + thiram at rate 1.5 showed superior control efficacy against maize thrips (Frankliniella sp.) with 96.06% and 95% population reduction, respectively, and maize leaf aphid (Rhopalosiphum maidis) with 97.37% and 96.67% reduction percentage, respectively. Hence, dressing of maize seeds before planting with such insecticides can be used for early-stage protection against potential vectors of the MLN causing viruses.