The Influence of Partial UV-blocking Films in the Insect Infestation and in the Growth of Broccoli and Turnip Seedlings

Abstract

The present work study the effect of partially UV-blocking films on the promotion of growth and insect control as well as the herbivores/sucking insects-predators proportion in the tunnels of Broccoli and Turnip seedlings is provided. During the experiment six treatments were tested: outdoor, UV-transmitting, and partial UV-blocking (UVs shorter than 340, 350, 360 and 400 nm) in three replications. Also a tunnel covered with UV-transmitting polyolefin film was also prepared, and the results were compared with the seedlings that were grown, outdoors. The plant height, leaf number and leaf area increased in Turnip, while Broccoli was not affected. The number of insects invaded into the tunnels were trapped using blue and yellow adhesive films, and Eight different insects including mosquitoes were listed viz.: Aphid (Brevicoryne brassicae), brown plant hopper (Nilparvata lugens), short horn grass hopper (Melanoplus femurrubrum), white backed plant hopper (Sogatella furcifera), dipteran fly, mirid bug (Heteroptera: Miridae), up to 30 days after planting. Aphid was found as the most predominant insect followed by mosquito, dipteran fly, and white baked plant hopper. The largest feeding damage was found in outdoor with 26% in Broccoli and 22.5% in Turnip. The ratio of the herbivores and predators was also influenced by the films and it was remarkable in both Broccoli (35-65%) and Turnip (25-75%) seedlings, respectively. The partial UV-blockings effectively reduced the feeding damage compared with the outdoors, irrespective of seedling. Therefore, the sticky traps were found to be effective, and partial UV-blocking films showed different effects in controlling insect pests. Hence, the partial UV-blocking films can be an effective component for the IPM system rather than fully UV-blocking films.