Thrips are one of the main pests on grapes, with adults and nymphs feeding on the sap of the young tissues of grapes, which will cause direct damage to leaves, buds and fruits when eating, which in turn affects yield and quality.
Because thrips have the characteristics of small insect body, good concealment, etc., and the early symptoms are not easy to be found, many fruit friends have neglected the prevention and control of the insect, and it is too late to think about treatment when the symptoms are manifested in the later stage.
1. Thrips on grapes
Thrips are the collective name of Thyroptera insects, individuals are tiny, only 1 to 2mm, the type of mouthparts is between the chewing type and the sucking type, for the unique file suction type, even scraping belt suction, so the ability to create injuries is strong.
Grapes are one of the hosts that thrips like to eat, and the thrips that are more harmful to grapes are smoke thrips, tea yellow hard thrips, westflower thrips, double-flowered thrips, rhododendron thrips, grape black thrips and so on.
Except for the tea yellow hard thrips, which are visible all year round on the young leaves of grapes, other types of thrips are only harmed during the flowering to young fruit stages of grapes, and are difficult to see after that.
Thrips are more parthenogenetic, rare males, eggs are more abundant under the dorsal skin and veins of the leaves, and the hatching nymphs are less active, concentrated on both sides of the dorsal veins of the leaves, and dispersed when they grow up.
Adult insects spread quickly, but afraid of sunlight, more than morning and evening or cloudy days out of harm, do not like high temperature, so in the summer high temperature period for the harm is reduced, such as the southern grape producing areas usually have May to June, August to October two peaks.
2. The harm of thrips to grapes
Thrips like to use its file suction mouthpiece to first file the young organs of plants such as new shoots, young leaves, flower organs, and young fruits before pricking the sap.
The leaves will first appear greenish yellow spots, and then the leaves will become smaller, curled, dried up, and sometimes perforated, and the growth of the new shoots of the victim will be inhibited.
The young fruit of the victim forms small longitudinal black spots on the surface of the fruit and concentrates on the middle or stem.
As the fruit expands, the dark spots expand into banded or irregular wood-bolted brown rust spots, and the cracking of the fruit is particularly severe.
Grape tobacco thrips
Grape tea yellow mite fruit
Some species, such as smoky thrips, also have raw flower spots and rust spots when they harm grape grains, which are similar to the symptoms of tea yellow mites. The main difference is that there is a pronounced wood peg at the thrips wound, while the tea mite has pale white stripes on the rust spots. In addition, tea mites can also harm grape stems, making them black and hard and crisp.
3. About the prevention and control of grape thrips
Agricultural control: in early spring, weeds and dead leaves of the park are removed, and the pest base is burned or buried deeply to reduce the source base of insects; the characteristics of sunlight are used to increase the ventilation and light transmission conditions of the grape canopy through reasonable pruning.
Biological control: The protection and use of natural enemies such as small flower bugs and cockroach bugs has an inhibitory effect on the occurrence of thrips.
Physical control: Hanging blue board booby traps.
Chemical control: before flowering to the young fruit stage, the new shoot stage is the peak of its occurrence, we must pay attention to the prevention and control of drugs, the agent can choose ethyl polybactericide, spironoid ethyl ester, flufenoxamnitrile, acetamide, thiamethoxine, avermectin, acetamidine, etc., pay attention to the rotation of medication, tree and ground spray combination.