Control methods for the mango shoot borer (Chlumetia transversa) pest and disease
(1) Damage Also called the shoot borer. It occurs commonly in mango-producing areas and is an important pest of mango. The larvae bore into and feed on young shoots and flower spikes; infested young shoots or flower spikes wither or grow weakly.
(2) Morphological characteristics Adult body length 11mm, wingspan 23mm. The dorsal side of the body is dark brown, the ventral side grayish white, the head brownish brown, the forewings tea-brown or grayish brown with distinct transverse lines; the hindwings grayish brown. The egg is flat and round, about 0.5mm in diameter, green when newly laid, later turning reddish brown, and fading in color before hatching. The pupa is 9.5-11mm long, short and stout, yellowish brown.
(3) Life habits In the Nanning area, 8 generations occur per year, with overlapping generations. In early October each year, pupae begin to overwinter in dead branches, bark crevices, and weeds. Adults begin to emerge in late January of the following year. Adults mostly emerge in the morning, are active and mate at night, and lay eggs 3-5 days after mating, mostly scattered on old leaves or young shoots; each female lays 50-400 eggs, averaging 200. Larvae mostly hatch in the morning and forenoon; newly hatched larvae mainly damage the veins and petioles of young leaves, and sometimes also damage flower clusters; after the 3rd instar they concentrate on damaging young shoots and flower spikes. The larvae have 5 instars in total, and mature larvae mostly pupate in dead branches, bark, or other insect shells.
(4) Control methods First, in winter, combine orchard cleaning, prune dead branches and rotten wood, and paint the tree trunks with 1:10 limewater to reduce the overwintering pest population. Second, tie straw around the tree trunks to attract larvae to pupate there, and regularly collect and burn it. Third, spray pesticides. During the egg stage and the early larval instars, use chemical control. Generally, when flower spikes and young shoots have grown 3cm, begin spraying, once every 7-8 days, for 2-3 consecutive sprays. The pesticides include 90% trichlorfon, 80% dichlorvos plus 40% dimethoate at 800-1000 times dilution, and 20% fenvalerate, 2.5% deltamethrin at 2000-3000 times dilution.