Abstract:
The blossom midge, Contarinia maculipennis Felt is a devastating pest of ornamental and vegetable crops. In recent years, C. maculipennis has emerged as a serious pest of tuberose, Agave amica (Medik.) Thiede & Govaerts, a widely cultivated flower crop in India. Despite its emerging global threat, its population ecology remains poorly understood. This study examines population ecology of C. maculipennis using an age-stage, two-sex life table approach, with particular emphasis on below-ground developmental stages and the influence of soil environmental conditions. The average fecundity of C. maculipennis was 39.13 ± 1.93 eggs, with an intrinsic rate of increase (r) of 0.137 ± 0.001 and a mean generation time (T) of 19.73 ± 0.01 days. The population doubling time was 5.05 ± 0.02 days, with the highest survival rate observed in the first instar larvae (0.95) and the lowest in the adult stage (< 0.38). Life expectancy peaked at age zero (e0 = 15.57 days) and decreased with age. The reproductive value (Vx) peaked between 13- and 19 days post-field appearance. Pupal development was fastest in sandy loam soil (9.67 days), with significantly higher adult emergence; however, pupal development and adult emergence were severely impacted in black cotton and marshy soils. Moderate soil moisture (20%) favoured pupation and eclosion rate, while dry (10%) and saturated (30%) soils hindered pupation and emergence. Population growth predictions over 90 days, starting with an initial population of 133 eggs, indicated that the adult population would reach 3,80,738. This study on vital statistics emphasizes the susceptibility of pupae and adults, marking these stages as crucial targets for controlling C. maculipennis. The soil type and moisture content significantly impact blossom midge survival and development. Techniques such as adjusting soil moisture during flowering, using drip irrigation to keep the area dry between crop rows, burying the pupae, and deep ploughing to bury pupae can effectively interrupt the midge life cycle.