What are the pest and disease control methods for yam cultivation

Yam has strong disease resistance and rarely gets sick, but in recent years anthracnose sometimes occurs, causing stem blight and leaf drop. Generally before sowing, soak the seeds with 50% carbendazim wettable powder 1000-1200 times dilution, or dip the wounds of yam planting sets in dry plant ash, or store yam planting sets, segments or aerial tubers in plant ash. If disease occurs at the seedling stage, spray with 50% carbendazim or mancozeb 800 times dilution, once every 7-10 days, 5-6 times is sufficient.

Yam pest damage is very serious, mainly underground pests, such as wireworms, mole crickets, and white grubs, which bore many holes in the underground tubers of yam, and sometimes still hide inside the tubers to dormancy. Wireworms themselves have a membranous layer, and chemicals are not easy to penetrate into their bodies for contact killing, so stomach-poison chemicals are better. It is best to adopt comprehensive measures for prevention, and the methods are as follows:

(1) Deep plowing: Deep plow the land 25-30 cm deep before winter, turn the overwintering adults and larvae to the surface, so that they freeze to death, die from sun exposure, or are preyed upon by natural enemies.

(2) Fertilization: Fully decomposed organic fertilizer can change the soil's aeration and water permeability, make crops grow robustly, and enhance disease and pest resistance. Crop rotation is also a powerful measure for disease and pest prevention, and generally rotating once every 3-4 years is better.

(3) Poisoned grain: Use 0.15 kg of 90% trichlorfon 30 times dilution, mix with blighted grain to make it, and apply 1.5-2.5 kg per 667 sq m. Spread it on the soil surface, then loosen the topsoil with a hoe, so that some of the chemical is in the soil and some is on the soil surface.

(4) Poison bait: Use 0.15 kg of 90% trichlorfon 30 times dilution, mix with 5 kg of fried fragrant wheat bran or soybean cake (or cottonseed cake) to make poison bait. Applying it on a windless, muggy evening gives good results. When mixing, add water 1-1.5 times the weight of the bait material. Or use 100 g of 40%-50% dimethoate emulsifiable concentrate mixed with 5 kg of water and 50 kg of bait material fried until fragrant (wheat bran, soybean cake, crushed corn kernels, etc.), dig a row about every 2 m, dig a bowl-sized pit every 3-4 m, place a pinch of poison bait and then cover with soil, using 1.5-2.0 kg of poison bait per 667 sq m. This method controls mole crickets and white grubs very well.

(5) Root irrigation: Use 40% isofenphos-methyl emulsifiable concentrate 1500 times dilution, irrigate 0.15-0.2 kg of solution per plant. Or use 2% isofenphos-methyl powder, 3-4 kg per 667 cubic m, scatter it on the topsoil near the plants, then mix the soil and powder evenly with a hoe. This method has a special effect on controlling white grubs and wireworms. Or use 90% trichlorfon 800 times dilution, irrigate 0.15-0.2 kg of solution per plant.