The grape larvae are mainly larvae damaging the shoots. The first instar larvae grazing under the epidermis, the skin of the damaged shoots slightly bulges and darkens, the worms settle in the tunnel, do not discharge, and are not easy to be found. After the larvae enter the xylem, the branches are often cut transversely, causing the branches to die and the wind to break easily.
According to investigations, in the Changshu region, the Tianzhugrass has occurred for one generation each year, wintering with young larvae in grapevine branches, and beginning to sprout after grape sprouting in mid-to-late April. As the age increases, the branches can be hollowed and the branches can fall off. In mid-June, mature larvae emerged near the fractures, and they emerged from mid-July to late August. The adults disperse the eggs in the gaps between the bud scales on the side of the shoots of new shoots, or in the gaps between buds and leaves, and after larvae hatch. From the bud into the stem.
Adult emergence and oviposition period is the key period to prevent and control grape tiger day beetles, but at this time, it is also the ripe period of grapes, and the safety intervals should be paid attention to when using drugs. The commonly used drugs include 10% cypermethrin (safety interval 15 days or more) and 90% crystal trichlorfon (safety interval 28 days or more). The grapes may be sprayed with systemic insecticides after harvesting, or they may be injected with 100% solution of 80% dichlorvos and blocked to kill the larvae.
The ability of the adult Tigergrass adult to fly is poor, and the artificial catching effect is good when the morning dew during adult spawning period is not dry. At the same time, the new feeding part of the affected shoot has obvious resin flow, which can be squeezed with fingers or backstabbed with scissors. Hit to kill larvae. In addition, during winter pruning, the black shoots near the section should be cut off and burned. After the spring buds, any shoots that fail to germinate or atrophy after germination are mostly larvae and cut off in time.
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