CHEMICAL CONTROL OF Leptodictya plana (HEMIPTERA: TINGIDAE) AND FOLIAR DAMAGE IN CULTIVARS OF Cenchrus purpureus

Abstract

Leptodictya plana Heidemann is an emerging pest of Cenchrus purpureus in Altamira, Tamaulipas, Mexico. This study evaluated the mortality of the lace bug (L. plana) by the effect of four insecticides at different doses: Alphacypermethrin + Imidacloprid (19:45, 39:90 and 54:135 ppm), Spinetoram (90, 120 and 150 ppm), Sulfoxaflor (225, 300 and 375 ppm) and Thiacloprid (200, 300 and 400 ppm), plus the control (distilled water plus 0.03 % Tween 20). Also, the foliar damage (%) caused by this pest in the cultivars of C. purpureus: Camerún, Caña Africana, Cuba CT-115, Elefante, King Grass, Maralfalfa, Mott, OM-22, Taiwan and Uruguana was assessed. The mortality in lace bugs with the application of Alphacypermethrin 8.45 % + Imidacloprid 19.72 % and Thiacloprid 40.40 % was 0.95 to 1.00 from 8 to 24 hours after application. Mortality at doses of 90 ppm (Spinetoram) and 225 ppm (Sulfoxaflor) was 0.76 and 0.73, respectively at eight hours after application, while at 24 hours it was > 0.99. The most significant foliar damage was observed in Mott and Camerún cultivars (71 and 62 %, respectively); the Uruguana, King Grass and Elefante cultivars presented the minor damage (between 21 and 28 %). The insecticides Alphacypermethrin + Imidacloprid and Thiacloprid caused a mortality of 1.00, thus, they can be used to control the lace bug.