Seasonal incidence, varietal response and spatial distribution of thrips on Mulberry (Morus spp.) accession under field conditions

Abstract

The study was conducted during 2024–25 at the Department of Sericulture, UAS, GKVK, Bengaluru, to understand how thrips infest mulberry across seasons and to identify resistant and susceptible accessions. One hundred mulberry accessions were evaluated during the rabi, summer and kharif seasons, and thrips populations were recorded at 15, 30, 45 and 60th days after pruning (DAP). Results showed clear seasonal variation. Thrips incidence was highest in summer due to high temperature and low humidity, moderate in rabi and lowest in kharif because of high rainfall and humidity. Among one hundred accessions, ME-86 (13.54), ME-01 (13.29), ME-52 (11.83) and M-66 (11.75) consistently recorded low thrips populations across all seasons, indicating stable moderate resistance. In contrast, MI-79 (34.63), MI-524 (26.25), MI-517 (23.08), MI-32 (31.54) and MR-2 (36.46) remained highly susceptible in all seasons. Spatial distribution analysis revealed significant variation across canopy leaf positions. Thrips populations increased from the apical leaf downward, peaking on the 4th leaf (5.08 thrips/leaf), followed by the 3rd and 5th leaves, reflecting a strong preference for semi-mature foliage. Basal and apical leaves supported minimal infestation. A significant accession and leaf-position interaction indicated that susceptible accessions allowed greater thrips buildup at preferred canopy levels, whereas resistant accessions restricted population establishment even under favourable feeding sites.