How to treat the disease of rhododendron

Rhododendron has certain requirements for planting conditions, it likes warm and humid climate, shade tolerance, drought tolerance, avoid sun exposure. Especially sensitive to water, the soil moisture is too much in the plum rain season, and the plant is easy to be waterlogged and cause the whole plant to die. The air humidity should not be too high at high temperature in summer, and the basin soil should not accumulate water, otherwise it is disadvantageous to the growth and flowering of rhododendron. So how to treat the disease of rhododendron?

Disease

The common diseases of rhododendron include leaf swelling, chlorosis, brown spot, coal fouling and so on.

① leaf swelling disease

Prevention and treatment: 0.5%-1% Bordeaux solution can be sprayed before the disease, especially when drawing tips and spreading leaves, and the diseased leaves can be removed in time. Spray 0.3% 0.5% Baumedo stone sulfur mixture or 1% Bordeaux solution 2 times 3 times before and after germination, once every 7 to 10 days.

② chlorosis

Prevention and treatment methods: regular supplement of iron can be adopted, that is, 0.2%-0.3% ferrous sulfate is sprayed on the leaves at the initial stage of the disease, slightly mixed with adhesive, sprayed once every 15-20 days, the effect is better.

Insect pest

Common pests include red spiders and web bugs.

① red spider

Prevention and treatment: it can be sprayed with 40% omethoate EC 800 × 1000 times, or with 20% dicofol 800 times solution, once a week, 3 times 4 times in a row.

② net bug

Prevention and control methods: remove fallen leaves and weeds near flowers and trees after winter and bury them or burn them to eliminate overwintering adults. From April to early May, after the emergence of overwintering adults and the occurrence of the first generation nymphs, 1000 times of dichlorvos EC or 50% borer pine emulsion were sprayed every 7 to 10 days for 2 consecutive times. It can also be buried with 5 g or so 3% carbofuran per pot, and the effect is good.