(1) Agricultural control: Clean the countryside, deal with residual plants, old leaves and weeds in time after harvest, and reduce the source of insects. Deep ploughing and harrowing should be done to avoid continuous cropping of cruciferous vegetables, reduce the source base of overwintering insects and control the harm. For Chinese cabbage, it can be covered with plastic film in early spring, planted and harvested in advance to avoid the harm of the second generation cabbage caterpillar; After the cauliflower is damaged, the compensation ability of vegetables can be used to delay the harvest time appropriately to make up for the losses caused by cabbage caterpillar.
(2) Physical control: protective cultivation and insect-proof nets can be used. Generally, a 25-mesh /m2 white insect-proof net or a silver-gray insect-proof net is used for tight coverage. The height of the small arch of the insect net should be more than 50cm, and a certain space distance should be kept from the leaves of Chinese cabbage to prevent cabbage caterpillar from laying eggs on the leaves.
(3) Biological control, protection and utilization of natural enemies of Pieris rapae. There are more than 60 known natural enemies of Pieris rapae, among which 10 has inhibitory effects. Natural enemies can be used to control Pieris rapae at a low level that does not cause economic harm for a long time, and the effect is lasting. The common natural enemies of Pieris rapae include Papilio, Trichogramma rubescens and Trichogramma.
(4) Chemical control: Due to the serious overlapping of generations of Pieris rapae, the food intake of larvae increased after the 3rd instar, and the drug resistance increased. Therefore, the pesticide should be applied before the second instar, with 50% phoxim EC 1000 times, 37% chlorfenapyr EC 3000 times, 25% quinalphos EC 2000 times, 25% deltamethrin 3000 times, 18% chlorfenapyr EC 500 times, or 20% cypermethrin. Or 40% chlorpyrifos EC 800 times, 2.5% dipyridamole EC 3000 times, 2.5% Baode EC 2000 times, 10% Niigata EC 1500-2000 times, 2.5% Tiannuo EC1.20 times. Or 25% Guang Zhi EC 600-800 times, 3.3% Tianding EC 1000 times, 80% trichlorfon soluble powder 1000- 1500 times, 0. 12% Tianlihao (Mi Chong Ding) wettable powder. Because the generation is uneven, it needs to be controlled continuously for 2~3 times.