Influence of filter cake application on wireworms harmfulness and sunflower productivity in the Krasnodar region

Larvae of click beetles (Coleoptera: Elateridae) are wireworms, one of the most spreading polyphagous soil pests damaging the agricultural crops, including sunflower. They prefer soils having pH from 5.6-6.0 to 4.5-5.0 and humus content more than 3.3%. Liming is the primary means to optimized reaction of a soil solution. In 2016-2018, in the V.S. Pustovoit All-Russian Research Institute of Oil Crops, influence of filter cake (lime organic and mineral fertilizers produced after sugar beet processing) application in doses 3.9 and 5.9 t/ha on damaging of sunflower seedlings by larvae of beetles from an Elateridae family (wireworms) and crop productivity. The dry filter cake in the studied doses introduced 30 days before sunflower planting with further incorporation into the physically mature soil by tillers “Krot” on a depth of 12-15 cm decreased significantly a number of wireworms - from 15-21 (in control) to 6-10 pcs/m2. Thinning of sunflower crops due to wireworm damages on average reached 53.3% in control, as plant death in variants with application of an organic and mineral fertilizer in doses of 3.9 and 5.9 t/ha was at a level of 31.6 and 26.7%, respectively. The filter cake application in doses of 3.9 and 5.9 t/ha allowed obtaining yield increase of 0.86-0.87 t/ha. Oil content in sunflower seeds in these variants was equal to 51.3-52.1%.