Effects of Net Barrier and Synthetic Insecticides on Phytolyma lata (Homoptera: Psyllidae) Infestation, Growth and Survival of Milicia excelsa in the Field

摘要

The effect of net barrier and synthetic insecticides on Phytolyma lata infestation, growth and survival of Milicia excelsa seedlings was investigated during the year 2010-2011 in Ibadan Southwest Nigeria. In a complete randomized design with three replications, a 2 in high netted barrier were laid out in unit plots of 15x15 m(2) using five treatments: Blue net+dimethoate+carbofuran, Green net+dimethoate+cabofuran, Blue net+dimethoate, Green net+carbofuran and dimethoate only (control). Plant height, stem diameter, number of branches, numbers of galls, Pytolyma lata density, plant mortality and survival of Milicia seedling were recorded at monthly interval for two years. The treatments showed a significant difference (p<0.05) over the control. The net barrier plants were free from P. lata infestation 12 months after planting. The combined treatments of blue net barrier, dimethoate and carbofuran recorded least number of galls (7.89%) on Milicia seedlings while combined treatments of green net, dimethoate and carbofuran recorded least population density of P. lata (13.59%). There was no significant difference (p<0.05) between the combined treatments of blue and green barrier nets on the plant growth, although blue net+dimethoate+carbofuran recorded highest plant height and stem diameter with mean of 122.50 cm and 1.03 mm, respectively. Integrated treated plots recorded 100% seedling survival while control plot recorded 54% seedling survival after two years. Integration of net barrier with carbofuran and dimethoate is economical and should be adopted for successful establishment of Milicia plantation.