POPULATION DYNAMICS, DAMAGE ASSESSMENT AND MANAGEMENT OF COCONUT MITE, ACERIA GUERRERONIS KEIFER IN SOUTHERN REGION OF BANGLADESH

Abstract

The study was made in the southern region of Bangladesh viz, Jashore, Satkhira, Barishal and Bagerhat as well as in the Central Laboratory of Sher-e-Bangla Agricultural University (SAU), Sher-e-Bangla Nagar, Dhaka, Bangladesh, during June 2015 to May 2017 to evaluate the population dynamics, damage assessment and management of coconut mite, Aceria guerreronis Keifer in southern region of Bangladesh. In the southern districts of Bangladesh, coconut growers’ were aware about the coconut mite as a major pest of coconut and also took some management practices against this mite. The study revealed significant variations in the average population of coconut mite on different aged coconut nuts. The highest population of coconut mite was observed in April, 2017 in Jashore region (18.44 coconut mites/ 4 sq mm), followed by in Satkhira region (14.81), in Barishal region (9.97) and in Bagerhat region (4.02 coconut mites/ 4 sq mm). On the other hand, the lowest population of coconut mite was observed in August, 2017 in Jashore region (0.85 coconut mites/ 4 sq mm), followed by in Satkhira region (0.51), in Barishal region (0.34) and in Bagerhat region (0.34 coconut mites/ 4 sq mm). There was distinct effect of weather factors on the population of coconut mite specially decline of population with high rainfalls. All coconut trees were infested by the coconut mite from September, 2016 to June, 2017 of Jashore, Satkhira, Barishal and Bagerhat districts of Bangladesh. On the basis of damage extent to coconuts the mean grading index in the month of June, 2017, Jashore region showed the highest value 4.40 following Satkhira region (4.11), Barisal region (3.89), Bagerhat region (3.61) and the South-West region of Bangladesh (4.00). The size of infested coconuts was affected the length, breadth and weight of coconut nut being 26.82 cm, 50.4 cm and 1.51 kg respectively for Grade-1 infested coconut nut, 24.32cm, 47.84 cm and 1.25 kg for Grade-2, 23.83 cm, 47.39 cm and 1.24 kg for Grade-3, 23.32 cm, 44.32 cm and 1.17 kg for Grade-4 and 22.23 cm, 42.99 cm and 1.01 kg, respectively for Grade5 infested coconut

nut. In the study of efficacy of chemical treatments against coconut mite, T 3

(Intrepid 10SC @ 4ml/L of water) showed the best performance with 100.00 % mortality while T 0

(untreated control) showed the lowest performance with 0.00 % at 12, 24 and 36 hours after treatment application. The treatment application as IPM in coconut orchard in Jashore region was effecti9ve in 12 months in IPM package P 4 (Intrepid 10SC @ 4ml/L of water and neem oil cake @ 5 kg/tree) that reduced the mite infestation at 1.67% over untreated plants.