INFLUENCE OF NITROGENOUS FERTILIZER ON INCIDENCE OF PEST AND OTHER ARTHROPODS OF QUINOA

Abstract

An experiment was conducted in the experimental field of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during the period from November, 2018 to March, 2019 to evaluate the influence of nitrogen fertilizer on insect pest complex of quinoa. The experiment was laid out in Randomize Complete Block Design replicated with three times. For this study treatments were, T 1 : 50 kg nitrogen fertilizer dose; T ii 2 : 100 kg nitrogen fertilizer dose; T : 150 kg nitrogen fertilizer dose; T 4 : 200 kg nitrogen fertilizer dose; T : 250 kg nitrogen fertilizer dose; T 6 5 : untreated control. The lowest aphid, whitefly and jassid, stink bug, flea beetle, grasshopper, spider, housefly infestation (3.71, 2.70 and 3.36, 2.78, 3.78, 1.78, 1.55, 3.44 respectively) on quinoa was recorded in T The lowest percent leaf infestation and percent plant infestation (24.31% and 36.23%, respectively) by insect pests on quinoa was recorded in T 1. The highest incidence of lady bird beetle per five tagged plants (3.34) on quinoa was recorded in T . Number of Apis mellifera per m 2 per minute at different day times was recorded highest in T which comprised with 250 kg nitrogen fertilizer dose and low in T 1 1. 5 3 5 . Number of Apis florea per m

per minute at different day times was aslo recorded highest in T which comprised with 250 kg nitrogen fertilizer dose and low in T 1 5 . So, from this study it was concluded that, the higher amount of nitrogen fertilizer treated field was more susceptible for different insect pest. The highest plant height, panicle length, panicle diameter and 1000 seed weight (54.79 cm, 28.13 cm, 12.52 cm and 2.89 gm respectively) of quinoa was recorded in T The highest yield per hectare (1.11 ton/ha) of quinoa was recorded in T 3. 3. As a result, the order of efficacy of different fertilizer doses in terms of yield is T 3 >T 4 >T 5 >T 2 >T 1 >T 6. It can be concluded that T may be the best dose for decreasing insect pests and increasing yield.