STUDY ON HOST PREFERENCE AND MANAGEMENT OF RICE WEEVIL (SITOPHILUS ORYZAE L.) USING SOME BOTANICALS UNDER STORAGE CONDITION

Abstract

The study was conducted in the laboratory of the Department of Entomology, Sher-eBangla Agricultural University, Dhaka from May 2018 to October 2018 to find the most

preferable grain by rice weevil (Sitophilus oryzae

L.) based on its biology and the most effective botanical insecticide to control the rice weevil in storage condition. The experiment was laid out in the ambient condition of the laboratory following in a Completely Randomized Design (CRD) and the treatments were replicated for four times. Among the grains (wheat, husked rice, unhusked rice, maize and chick pea) considering wheat, rice weevil was given the highest number of progenies for all 1

generation (90.33, 130.67 and 195.33). All the other grains resulted significantly different number of progeny but the lowest was obtained from unhusked rice grain (78.33 and 113.33) for 1 st and 2 nd generation and 185.33 from maize at 3 ii rd generation. The highest number of rice weevil larvae (5.67) was found in wheat grains. Number of adults were highest 35.33 in wheat grains while the lowest in husked rice (11.67). According to the observations, neem leaf powder (67.67 dead rice weevil) showed significantly very high insecticidal effect on Sitophilus oryzae adults at 1 day after treatment application. Mehogoni leaf T 1 (51.67 dead rice weevil), marigold leaf T 3 (48.67 dead rice weevil) and garlic powder T 4 (34.67 dead rice weevil) were followed by neem leaf. Percent mortality of some botanical insecticides, neem leaf T 2 st , 2 (4% dead rice weevil), garlic powder T 4 (3% dead rice weevil) and marigold leaf T 3 (2.33% dead rice weevil). The highest weight of healthy seeds was recorded in T 2 (96.40 g) treatment which was statistically similar with T 1 (91.28 g), whereas the lowest in T 6 (79.76 g) untreated control treatment. In case of % infestation, the highest infestation was found from T 6 (19.96%) which was followed by T 5 (15.82%) treatment while the lowest in T 2 (3.18%) treatment. The highest percent infestation reduction over control was recorded in T 2 (84.07%) treatment and lowest from T 5 (20.84%) treatment. So, from the above findings, it can be said that neem leaf powder was found the best one to control rice weevil infestation as well as wheat grains were the most preferred host for rice weevil.