How to control corn thrips? An introduction to practical control methods

In corn fields, damage from thrips often occurs. Farmers growing corn must control thrips in a timely manner. How to control corn thrips? Let's find out together below.

1. How to control corn thrips?

1. During winter and spring, in combination with collecting manure, remove weeds along field edges, ditch edges and pond edges, and clear away dead branches and fallen leaves beside field ridges and plots, especially removing Chinese sprangletop and other grass-family weeds.

2. During the peak outbreak period of thrips, use chemical spraying for control. The chemicals can be: 10% imidacloprid wettable powder at 2500 times dilution, or 2.5% Baode emulsifiable concentrate at 2000-2500 times dilution, or 50% fenitrothion emulsifiable concentrate at 500 times dilution, or 90% trichlorfon crystal at 1500 times dilution.

2. Occurrence patterns of corn thrips

1. Corn yellow thrips (Anaphothrips obscurus): adults overwinter at the base of grass-family weeds and inside dead leaves. In northern regions, they generally migrate from grass-family plants to corn in mid-to-late May, and reproduce for 2 generations on corn. First-generation nymphs occur on spring corn from late May to early June, and by mid-June they enter the adult peak period, which is also the peak damage period. During the corn seedling stage, adults and 1st-2nd instar nymphs cause severe damage by piercing and sucking the corn whorl, while 3rd-4th instar nymphs stop feeding.

2. Grass thrips (Frankliniella tenuicornis): adults and nymphs are relatively active and mostly prefer to gather on the front side of corn whorl leaves to cause damage. This pest mainly occurs around the corn funnel stage, and at an average daily temperature of 21-27°C, it completes 1 generation in 10-18 days.

3. Rice tube-tailed thrips (Haplothrips aculeatus): adults have strong phototaxis and overwinter as adults. Adults like to move about inside the corn funnel, but after corn tasseling, large numbers gather on the tassels to cause damage and reproduce.

3. Damage caused by corn thrips

Corn thrips is also called slim-horned thrips or grass thrips. There are only three kinds of thrips that harm corn, namely corn yellow thrips, grass thrips and rice tube-tailed thrips. The larvae of thrips can bore into the glumes to cause damage, resulting in empty shriveled grains, generally accounting for about 10% empty shriveled grains, making it an important pest of rice. It is distributed in Inner Mongolia, Liaoning, Fujian, Guangdong, Guangxi, Sichuan, Yunnan, Tibet, Shaanxi, Gansu, Qinghai, Ningxia, Xinjiang, Jiangxi, Henan and other provinces and regions.

Corn thrips mostly move about and cause damage inside the whorl leaves of host plants. When feeding on leaves that are still expanding, they mostly feed on the front side of the leaves, causing patches of silvery-gray spots on the leaves. Severe damage by corn thrips can cause large numbers of dead seedlings.

The damage caused by corn thrips is relatively great, so timely control is needed to reduce the damage.