Corn diseases and pests are more severe than in previous years; here are the key control measures for your reference.

Recently, the National Agricultural Technology Extension Center convened relevant experts to forecast this year’s trends in corn diseases and pests, concluding that 2018 will see a more severe outbreak than usual, with a cumulative affected area potentially reaching 1.08 billion mu‑times. Based on these scientific projections, the experts ultimately formulated the “2018 Technical Plan for the Prevention and Control of Major Corn Diseases and Pests.”

According to analyses and forecasts jointly prepared by the National Agricultural Technology Extension Center and relevant experts, in 2018, the incidence of corn diseases and pests nationwide is expected to be more severe than usual. In the Northeast and North China regions, the fall armyworm, cotton bollworm, underground pests, and northern leaf blight are particularly damaging; in the Huanghuaihai region, the fall armyworm, cotton bollworm, two-spotted armyworm, and brown spot disease are especially prevalent; and in the Northwest and Southwest, the cotton bollworm, aphids, spider mites, fall armyworm, and southern rust are widespread. The total affected area is projected to reach 1.08 billion mu‑times. To effectively control major corn diseases and pests, this plan has been specially formulated.

Prevention and Control Objectives

The treatment rate for major corn diseases and pests exceeds 90%, with an overall control efficacy of over 80%; damage and yield losses are kept below 5%, and the coverage of specialized, unified pest management reaches at least 36%. Efforts will be further intensified to expand the area under green pest‑management practices.

Prevention and control strategy

For key pests and diseases in different corn-growing regions and developmental stages, prioritize the use of resistant and tolerant varieties, supported by green pest‑management technologies, and vigorously promote professional, integrated pest‑management services. Emphasize comprehensive, environmentally friendly control throughout the entire growth cycle, implementing practices such as straw crushing and return to the field, seed treatment, early‑stage pest and disease management, Trichogramma wasp–based borer control, and mid- to late‑season pest and disease management, thereby reducing costs, increasing efficiency, and ensuring the safety of corn production.

Prevention and control measures

I. Key Prevention and Control Priorities by Region

Northern Spring-Planted Corn Region

Key pests and diseases to be controlled include the corn borer, the two-spotted long-legged leaf beetle, underground pests, the second- and third-generation armyworms, northern corn leaf blight, stalk rot, corn nematode‑induced stunting, and gray leaf spot.

Yellow-Huai-Hai Summer-Planted Corn Region

Key pests and diseases to be closely monitored and controlled include the corn borer, cotton bollworm, second-generation armyworm, corn aphid, two-spotted armyworm, thrips, stalk rot, southern rust, brown spot, curvularia leaf spot, and small spot.

Corn-growing region of the southwestern mountainous and hilly areas

Key pests and diseases to be controlled include the corn borer, second- and third-generation armyworms, sheath blight, northern leaf blight, gray leaf spot, and ear rot.

Northwest Corn Region

Key pests and diseases to be controlled include underground pests, corn aphids, spider mites, European corn borer, two-spotted leaf beetle, stalk rot, and northern corn leaf blight.

II. Key Pest and Disease Control Measures

1. Corn borer

Straw is crushed and returned to the field to reduce the initial pest population. During the emergence period of overwintering adults, insecticidal lamps combined with sex pheromone traps are used for mass trapping. In the early egg‑laying stage, Trichogramma wasps are released to parasitize and destroy eggs. At the heart‑leaf stage, Bacillus thuringiensis preparations are applied by spraying, or a tank mix of chlorantraniliprole, thiamethoxam, lambda‑cyhalothrin, and matrine is used to enhance control efficacy while also managing aphids and spider mites.

2. Underground pests and seedling-stage pests such as thrips, aphids, and leafhoppers Seed treatment is carried out using agents such as thiamethoxam and cyantraniliprole.

3. Root rot, smut, and stem rot, among others

Select disease-resistant varieties. Treat seeds with fludioxonil–metalaxyl‑M suspension seed coating or with seed coatings containing benzenesulfonamide, tebuconazole, and other active ingredients.

4. Corn leaf spot diseases

Select disease-resistant varieties, practice appropriate planting density, and apply fertilizer scientifically. During the late heart-leaf stage of maize, spray with agents such as difenoconazole, epoxiconazole, pyraclostrobin, and jinggangmycin A; depending on the severity of the disease, repeat the application every 7 to 10 days. In areas where brown spot is prone to recurrence, initiate control measures when the plants have 8 to 10 leaves. Mixing these fungicides with brassinolide can enhance their efficacy.

5. Corn sheath blight

Select disease-resistant and tolerant varieties, and maintain an appropriate planting density. At the onset of the disease, remove the infected leaf sheaths at the base of the stem, and combine this with foliar applications of biopesticides such as Jinggangmycin A, or chemical fungicides like Juncanqing, Epoxiconazole, and Mancozeb. Depending on the severity of the infection, repeat the spray every 7 to 10 days.

6. Corn aphid

During the tasseling stage of maize, apply insecticides such as thiamethoxam, imidacloprid, acetamiprid, and pymetrozine at the onset of aphid infestation.

7. Corn leaf mite

Promptly remove weeds along field edges and at field corners. When localized outbreaks occur, apply sprays containing pyridaben, etoxazole, propargite, or abamectin, focusing on the undersides of the middle and lower leaves of corn plants around the field perimeter and on weeds at the field edges.

8. Cotton bollworm

In the early stages of egg laying, release Trichogramma pretiosum to suppress egg populations; alternatively, during the peak of egg hatching, apply Bacillus thuringiensis formulations, emamectin benzoate, chlorantraniliprole, and other insecticides.

9. Two-spotted armyworm

Cultivate winter‑fallow fields thoroughly; before sowing, eliminate or clear stubble and remove any mulch from the corn planting furrows. For chemical control, options include chlorantraniliprole and emamectin benzoate; methods such as foliar spraying, baiting with poisoned lures, and broadcasting poisoned soil can be employed.

III. Key Technologies Promoted for Specialized, Unified Pest and Disease Control

1. Straw management and deep tillage for stubble control technology

Implement straw crushing and return to the field, deep tillage, and pre-sowing stubble removal to disrupt the habitats of pests and diseases and reduce their initial population levels.

2. Adult insect trapping and killing technology

During the adult emergence period of pest insects, insecticidal lamps can be used for mass trapping; for the overwintering generation of the European corn borer, mating pheromone traps can be employed in conjunction with these lamps.

3. Seed Treatment Technology

Based on the types of underground pests, soil-borne diseases, and seedling-stage pests and diseases, select an appropriate seed coating agent and apply a uniform seed coating.

4. Pest Control Techniques During the Seedling Stage

Based on the incidence of second-generation armyworms, thrips, brown planthoppers, beet armyworms, and cotton bollworms during the seedling stage, apply insecticides such as emamectin benzoate and chlorantraniliprole by spraying for control. In fields where nicosulfuron‑sulfonylurea herbicide has been applied, avoid using organophosphate pesticides to prevent phytotoxicity.

5. Pest and Disease Control Techniques for the Mid-to-Late Growth Stages

In the late vegetative stage, apply biopesticides such as Bacillus thuringiensis and Beauveria bassiana by uniform spraying to control corn borer larvae. Based on the incidence of mid- to late-season leaf spot diseases, ear rot, corn borers, cotton bollworms, aphids, and other pests, mix insecticides with fungicides to manage late-stage leaf spot diseases and pests like corn borers, cotton bollworms, and aphids. Promote the use of high‑stalk crop sprayers and aerial application technologies to enhance pest‑management capabilities during the mid- to late growth stages.

6. Trichogramma-based pest control technology

During the early to peak egg‑laying periods of pests such as the European corn borer, cotton bollworm, and peach fruit borer, release 15,000 to 20,000 parasitoid wasps per mu, establishing 3 to 5 release points per mu and conducting a two‑stage, synchronized release. In different regions, locally dominant parasitoid species should be selected to enhance control efficacy.

China Pesticide Industry Association (Source: Crop Helper)