There are many small white flying insects on the leaves of chrysanthemum. How to treat them?

Wipe off the insects on the leaves with washing powder water first, and then water the flowers with diluted washing powder, but not too thick and too many times. You can do it twice a month. The rest of the time with water, pay attention to ventilation. The most important thing is ventilation and plenty of sunshine. Don't water too much when flowering.

This insect is called white butterfly, and its control measures are as follows:

Physical prevention and control

1. Intercropping cruciferous plants, such as cabbage or cauliflower, in Banlangen field to induce adults to produce.

White butterfly with cabbage

Eggs, and then focus on killing larvae; Plow the fields in time after harvest in autumn.

2. Clean the site. After the cruciferous vegetables are harvested, the old leaves and weeds in the field should be removed in time to reduce the breeding grounds of Pieris rapae and eliminate some pupae. Deep tillage and fine harrow to reduce overwintering insect source.

3. Pay attention to the natural control function of natural enemies and protect natural enemies such as Trichogramma kwangtungensis, Trichogramma kwangtungensis and Papilio. At the peak of cocoon bee occurrence, 800 times of Cordyceps sinensis solution or Bt wettable powder containing more than 654.38+000 billion live spores per gram was sprayed.

biotic-control

In the early stage of larvae, spraying Bacillus thuringiensis 800- 1000 times or using 20 larva units per mu has a good control effect on Pieris rapae, and the best spraying time is in the evening.

Chemical control

(1) Before the 2nd instar, 500 ~ 1 000 times of Bt, 2,000 ~ 2,500 times of 1% pesticide emulsifiable concentrate or 0.6% pesticide emulsifiable concentrate 1 500 times can be sprayed.

(2) 20% diphenylurea SC 800 times, 10% Mibaike EC 1500 times, 50% phoxim EC 1000 times, 20% fenpropathrin 2000-3000 times, 265438+ and so on can be selected for the larval peak period.

(3) Due to the serious overlapping of generations of Pieris rapae, the food intake of larvae after the 3rd instar increased, and the drug resistance increased. Therefore, the pesticide should be applied before the second age, and 2.5% Caixi SC 1 000 ~ 1 500 times, 5% Regent SC 2 500 times, 10% except SC 2 000 ~ 2 500 times, or 24% Man Mei SC 2 000 ~ 2 500 times can be selected. Or 800 ~ 1.500 times of 3.5% Than Shwe EC, 2000 times of 20% Stryker SC, 3000 times of 2.5% plate angle EC, 2000 times of 2.5% Baode EC, or 10% extermination EC. Or 2 000 ~ 3 000 times of 2.5% Dakang EC, or 1 000 ~ 65 438+0 500 times of 5.7% Tianwang Bai Shu EC, or 600 ~ 800 times of 25% Guang Zhi EC, or 1 000 times of 3.3% Tianding EC, or 52.