How to prevent and control asparagus bean blight? Master these methods to reduce losses
The asparagus bean, also called cowpea, is a vegetable abundant in summer. It belongs to the cultivated species of the cowpea species that can form long pods, an annual twining herbaceous plant. Also known as asparagus bean, long-horn bean, banded bean, and skirt bean. It contains various vitamins and minerals, etc. The asparagus bean's root system has weak regeneration capacity, so direct seeding is mostly used; the optimum germination temperature is 25-30°C, and the air temperature at sowing should be above 20°C.
Morphological characteristics of the asparagus bean
Annual twining, herbaceous vine or nearly erect herb, sometimes twining at the tip. Stem nearly glabrous. Pinnately compound leaves with 3 leaflets; stipules lanceolate, about 1 cm long, decurrent into a short spur at the point of attachment, with line markings; leaflets ovate-rhombic, 5-15 cm long, 4-6 cm wide, apex acute, margin entire or nearly entire, sometimes pale purple, glabrous. Racemes axillary, with long peduncles; 2-6 flowers clustered at the tip of the inflorescence, often with fleshy glands between the pedicels; calyx pale green, bell-shaped, 6-10 mm long, lobes lanceolate; corolla yellowish-white with a slight bluish-purple tinge, about 2 cm long, each petal with a claw, standard petal oblate, about 2 cm wide, apex slightly concave, base with slight auricles, wings slightly triangular, keel slightly curved; ovary linear, pubescent. Pods pendulous, erect or spreading obliquely, linear, 7.5-70 (90) cm long, 6-10 mm wide, slightly fleshy and inflated or firm, with many seeds; seeds oblong-elliptic or cylindrical or slightly kidney-shaped, 6-12 mm long, yellowish-white, dark red or other colors. Flowering period May-August.
How to prevent and control asparagus bean blight?
Symptoms of asparagus bean blight
It mainly damages stems, leaves and pods, mostly occurring at or near the stem nodes, especially near the ground. The diseased part is initially water-soaked, then rots and constricts around the stem, and the leaves and vines above the diseased part wither and die. When humidity is high, the cortex rots and white mold appears on the surface. Infected leaves initially show dark green water-soaked spots, which later expand into round light brown spots with white mold on the surface. The diseased parts of infected pods also develop white mold and rot.
Control measures for asparagus bean blight
1) Select disease-resistant varieties.
2) Practice crop rotation. Choose well-drained sandy loam for planting, use high beds with deep furrows, plant at a reasonable density to allow ventilation and light penetration, and pay attention to timely drainage after rain.
3) Chemical control. Spray promptly for protection at the early stage of disease onset. 58% Ridomil MZ soluble powder at 500-800 times dilution, 64% Sandofan wettable powder at 500 times dilution, 72.2% Previcur aqueous solution at 800 times dilution; spray once every 7-10 days, for 2-3 consecutive times, for good results.