How to Use Pesticides for Wheat Stripe Rust and Fusarium Head Blight? A Detailed Guide to Control Methods

Currently, this is an important period for wheat yield formation, and also a critical period for pest and disease control. Affected by recent repeated rainfall events in the Jianghuai region and the middle and lower reaches of the Yangtze River, combined with a high base level of fungal inoculum in the field, the risk of fusarium head blight epidemics has increased, showing a trend of severe recurrence and spread. Agricultural departments are strengthening control measures to “snatch grain from pests” and ensure a bumper harvest.

According to the national pest and disease monitoring and forecasting network, as of May 4, the cumulative affected area of wheat pests and diseases reached 410 million mu, a year-on-year increase of 12%; the cumulative control area reached 380 million mu-times. Among these, the cumulative affected area of stripe rust was about 47 million mu, with a control area of 50.76 million mu-times. The cumulative affected area of fusarium head blight was 5.84 million mu, with a cumulative preventive area of 74.6 million mu-times.

Agricultural departments will take measures such as intensified monitoring and early warning, carrying out unified prevention and control, providing precise guidance services, and strengthening supervision and inspection to control wheat fusarium head blight. So, how should farmers apply pesticides to control wheat fusarium head blight and stripe rust? Now, the editor has compiled and published the chemical control techniques, hoping to provide help to everyone.

Wheat Fusarium Head Blight

In the middle and lower reaches of the Yangtze River and the Huang-Huai region and other areas where the disease is prevalent year-round, on the basis of strengthening healthy cultivation, it is necessary to grasp the critical period of wheat heading and flowering, apply pesticides when flowers appear, and take proactive prevention to curb the disease epidemic. For highly susceptible varieties, during the wheat heading to flowering stage, if the weather forecast predicts rainy, dewy, and foggy weather in the next 2 days, the first application time should be advanced to the booting to heading stage. Pesticide varieties can be selected from phenamacril, prochloraz, tebuconazole, carbendazim, thiram, thiophanate-methyl, enoxastrobin·carbendazim, enoxastrobin·tebuconazole, trifloxystrobin·tebuconazole, Bacillus subtilis, Jinggang·waxmycin, etc. Sufficient spray solution volume should be used. If rain occurs within 3~6 hours after application, timely re-treatment should be carried out after the rain. If severe disease epidemics occur, after the first control is completed, spraying should be repeated 1~2 times at an interval of 5~7 days to ensure control effectiveness. In areas where high-level resistance to carbendazim has developed, benzimidazole fungicides should be discontinued, and rotation and mixing of pesticides should be advocated. In areas where fusarium head blight occurs occasionally, combined control can be carried out during the heading and flowering stage along with the control of other pests and diseases.

Wheat Stripe Rust

Strengthen disease monitoring and implement zoned control. In the southwest, the Han River basin, southern Henan, and Longnan in Gansu and other main overwintering areas, diseased fields must be blockaded, and the preventive measure of “scouting with pesticides, treating spots to protect the whole field” should be fully implemented to reduce the spread of inoculum to the outside, prevent its spread to the Huang-Huai and North China wheat regions, and reduce the epidemic risk in late-maturing winter wheat and spring wheat regions. In the Huang-Huai spring epidemic area, implement the control strategy of “find one spot, control one area,” and promptly control the disease center; when the average rate of diseased leaves in the field reaches 0.5~1%, organize large-scale emergency control, and achieve full coverage of control in similar areas. Control pesticides can be selected from triadimefon, diniconazole, tebuconazole, epoxiconazole, hexaconazole, propiconazole, kresoxim-methyl, pyraclostrobin, pyrimidine nucleoside antibiotics, enoxastrobin·tebuconazole, etc.

In addition to focusing on controlling the above two diseases, to achieve a bumper wheat harvest, the following pests and diseases must also be controlled. The chemical control techniques are compiled as follows:

Wheat Sheath Blight and Powdery Mildew

From wheat green-up to the early jointing stage, when the rate of plants with sheath blight reaches about 10%, spray control should be carried out. Pesticides can be selected from tebuconazole, propiconazole, diniconazole, validamycin A (choose high-content formulations), polyoxin, Trichoderma, Jinggang·waxmycin, etc. When the rate of diseased leaves with powdery mildew reaches 10%, spray control should be carried out. Commonly used pesticides include triadimefon, diniconazole, myclobutanil, propiconazole, epoxiconazole, tebuconazole, prochloraz, kresoxim-methyl, fenaminstrobin, etc. In severely affected fields, spray again at an interval of 7~10 days. Sufficient spray solution volume should be used, aimed at the base, evenly and thoroughly sprayed, to improve control effectiveness.

Wheat Blossom Midge

In high-density areas, focus should be placed on two key links: soil treatment during the mid-pupa stage and pesticide spraying during the adult stage. In general occurrence areas, mainly carry out adult control before heading to flowering. For pupa stage control, during the wheat booting stage, when each small soil sample (10×10×20cm) contains more than 4 pupae, select phoxim, fenthion, etc. to make toxic soil, evenly broadcast along wheat rows; watering after broadcasting toxic soil gives better results. During the wheat heading stage, when there are more than 25 adults per 10 sweep-net passes, or when parting the wheat rows with both hands reveals more than 2 adults at a glance, promptly select pesticides such as phoxim, chlorpyrifos, beta-cyhalothrin, cyhalothrin·imidacloprid for spray control. In severely affected areas, apply continuously 2 times at 3-day intervals to ensure effectiveness.

Wheat Aphids

When the aphid population at the seedling stage reaches more than 500 per 100 plants, focused spot treatment should be carried out. When the aphid population at the ear stage reaches more than 1000 per 100 plants in the field, and the beneficial-to-pest ratio (natural enemies: aphids) is below 1:150, pesticides such as acetamiprid, imidacloprid, pirimicarb, beta-cyhalothrin, matrine, Verticillium lecanii, etc. can be selected for spray control. When pests and diseases occur simultaneously at the wheat ear stage, timely comprehensive control at the ear stage should be carried out. In areas with conditions, releasing Aphidius wasps for biological control is advocated; in North China wheat regions and other aphid immigration areas, in mid-to-late March, yellow sticky traps can be placed in the field to trap and kill immigrating winged aphids, so as to reduce the pest population base and alleviate damage at the ear stage.

Wheat Spider Mites

During the green-up and jointing stage, when the average mite population per 33 cm of row length reaches more than 200, pesticides such as abamectin, bifenthrin, malathion·phoxim, bifenthrin·triazophos, etc. can be selected for spray control. At the same time, agricultural measures such as deep plowing, weed removal, increased fertilizer application, and irrigation can be used for control.

Common Pesticide Types for Wheat Pests and Diseases

Insecticides: imidacloprid, acetamiprid, pymetrozine, thiamethoxam, deltamethrin, beta-cyhalothrin, beta-cypermethrin, fenvalerate, dichlorvos, pirimicarb, abamectin, matrine, etc. Among these, imidacloprid and acetamiprid should not be used alone; they should be reasonably mixed with low-toxicity organophosphorus pesticides for spraying.

Fungicides: triadimefon, diniconazole, tebuconazole, hexaconazole, propiconazole, difenoconazole, prochloraz, epoxiconazole, carbendazim, thiophanate-methyl, phenamacril, Bacillus cereus, validamycin, etc.