Occurrence Trend and Integrated Control of Diseases,Pests and Weeds in Wheat in the Middle and Late Stages

As the growth of wheat was impacted by the winter drought in 2007 and the low temperatures and frost damage from January to February in 2008, the proportion of high-quality wheat decreased, while the share of lower-quality types increased. Following the spring return of wheat, enhancing management practices in spring wheat fields—particularly focusing on disease and pest control during the later stages—became critical for achieving a successful 2008 harvest. **I. Trends in Wheat Diseases, Insects, and Weeds in 2008** Based on current data from wheat and poultry pest monitoring stations, along with an analysis of regional wheat resistance and spring weather conditions, it is predicted that mid- to late-season diseases, weeds, and pests will be more prevalent in the province this year. Key issues include wheat sheath blight, stripe rust, leaf rust, leaf blight, powdery mildew, scab, wheat cyst nematode, midge, underground pests, aphids, and wheat spiders. (a) **Wheat Field Weeds**: Moderate occurrence, covering 35–40 million mu, with common species such as leeks, wild garlic, sow thistle, valerian, motherwort, wild rape, maimai, and wild oats. (b) **Sheath Blight**: Expected to occur heavily, especially in areas with high population density, affecting 45–48 million mu. The peak period is expected to last until late April. (c) **Stripe Rust**: Moderate occurrence, but with potential for severe outbreaks in Nanyang, Xinyang, and Zhumadian, covering 10–15 million mu. The disease typically appears from mid-April to early May. (d) **Leaf Rust**: Moderate occurrence, mainly in central Henan, affecting 18–25 million mu. The damage period is in late May. (e) **Leaf Blight**: Moderate occurrence, with some regions experiencing higher intensity, covering 20–22 million mu. The danger period runs from late April to late May. (f) **Powdery Mildew**: Moderate occurrence in certain areas, particularly in irrigated high-yield zones, covering 22–27 million mu. The peak occurs from early April to early May. (g) **Scab**: If rainy weather occurs between late April and early May, scab could affect over 15 million mu. (h) **Wheat Cyst Nematode**: Light occurrence, mainly in Xuchang, Zhengzhou, and Jiaozuo, covering 15–18 million mu. (i) **Wheat Midge**: Overestimated occurrence, with local reoccurrence in areas like Pingdingshan, Zhumadian, and Luohe, covering 17–20 million mu. Adult emergence occurs in late April. (j) **Underground Pests**: Heavy occurrence, affecting 35–42 million mu. (k) **Aphids**: Moderate occurrence during the seedling stage, with heavy infestations during heading. Some areas in northern and western Henan may see 50–60 million mu affected. The damage period ends in mid-May. (l) **Wheat Spiders**: Moderate occurrence, mainly in hilly and dry areas, covering 20–25 million mu. The damage period lasts from late March to mid-April. **II. Comprehensive Control Measures for Wheat Diseases and Pests** (a) **Jointing Period**: Focus on controlling weeds, sheath blight, wheat spiders, and golden needle beetles. For broad-leaved weeds, use 75% superstar dry suspension (1–1.5g), 10% tribenuron-methyl (10–15g), or 20% chlorpyrifos emulsifiable concentrate (50–60ml). For general weeds, apply 6.9% fluazifop-P-butyl emulsion (60–70ml/acre) or 3% Sema EC (25–30ml). For sheath blight, use 20% Jinggangmycin wettable powder (30–40g/acre) or 12.5% diniconazole (20–30g). For wheat spiders, apply 40% omethoate EC (1000x dilution) or 0.9% abamectin EC (3000x). For underground pests, use 40% chlorpyrifos EC or 50% phoxim EC (800–1000x). (b) **Boot to Heading Stage**: Focus on powdery mildew, sheath blight, rust, aphids, midge, and red spider. Mix 40% chlorpyrifos (50–60ml/acre) with 0.9% abamectin (10–15ml), or combine 10% imidacloprid (10–20g) with 12.5% diniconazole (30–40g). During midge outbreaks, mix 3% methylisothion (3kg) with 5% phoxim granules (3–5kg), spread evenly over 20kg of soil, and water after application. (c) **Heading to Filling Period**: Address aphids, armyworms, midge, stripe rust, leaf rust, leaf blight, powdery mildew, and head blight. Apply 12.5% diniconazole (30–40g/acre), 20% triadimefon (60–80ml), or 25% propiconazole (30–35ml) mixed with 50% mancozeb (8–10g). For midge and disease-prone areas, mix 4.5% lambda-cyhalothrin (20–30ml) or 2.5% cypermethrin (25–30ml) for effective control. **III. Key Points for Effective Disease and Pest Management** To improve control efficiency, reduce pesticide waste, and minimize environmental impact, six key points should be considered: 1. Use biological or high-efficiency, low-toxicity pesticides instead of highly toxic ones like methyl parathion or monocrotophos. 2. Apply pesticides based on prevention thresholds; treat all fields meeting the criteria promptly. 3. Rotate and mix pesticides to avoid resistance development and maintain effectiveness. 4. Ensure proper application techniques, such as targeting the base of stems for sheath blight, and upper parts for aphids and midge. 5. Observe safety intervals, stopping pesticide use at least 15 days before harvest. 6. Apply nitrogen and potassium fertilizers appropriately to prevent premature leaf aging, prolong photosynthesis, and increase yield and quality.

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