Mango Shoot Psyllid
Females lay ovoid, brown-black eggs into the midrib or blade on the underside of leaves during spring. About 200 days after ovoposition, nymphs hatch and crawl to nearest buds and feed on them. The piercing and injection of chemicals into plant tissues while feeding induces the formation of hard, dark green cone-shaped galls in place of the buds. This prevents proper inflorescence and fruit settings. Dieback of infested branches may occur in case of severe infestation. Losses depend on the number of eggs laid and the consequent effect on the inflorescences. Apsylla cistellata reportedly is a serious pest in India and Bangladesh.
Adults are 3 to 4 mm long with brownish black heads and thorax, and light brown abdomen and variegated membranous wings. They are inserted by puncturing the tissue along both sides of the midrib or forming a line on the dorsal surface of the leaf. Eggs hatch after about 200 days and early nymphs are yellowish in color. After emergence they crawl to adjacent tender buds to suck cell sap. The chemicals they inject into the plant tissues while feeding induce the formation of green conical galls. There, the nymphs resume a six month-long cycle before reaching adulthood. Emerging adults will fall from the galls to the ground, where they get rid of coat remains. Later on, they climb up the trees to mate and lay eggs.
Application of industrial ashes rich in silicates is recommended. Infected twigs and shoots should be pruned 15-30 cm from the location where disease symptoms appear to significantly reduce the quantity of galls.
Always consider an integrated approach with preventive measures together with biological treatments if available. Spread the bark with dimethoate paste (0.03%) to decimate the psyllids that are moving up and down the tree. Injection of dimethoate into the bark might also work. At early stages of psyllid infestation, foliar sprays based on phosphamidon, methyl parathion, fenitrothion and monocrotophos (0.04%) also show good results.