What are the control methods for the Comstock mealybug on golden-leaf privet?

In Hengshui, Hebei, golden-leaf privet once suffered damage from the Comstock mealybug, which at the time caused the death of large patches of golden-leaf privet. Through research and control efforts in recent years, good results have been achieved. The control experience is summarized as follows:

The Comstock mealybug (Pseudococcus comstocki) is also known as the mulberry mealybug. Its eggs are generally laid between the leaf stalk and the branch, oval in shape, light orange-yellow, with dozens of them gathered into a mass, forming a white flocculent egg sac. It produces 3 generations per year. The peak occurrence period of the first-generation nymphs is mid-to-late May, the second generation peaks in mid-to-late July, and the third generation peaks from late August to early September.

Damage is mainly caused by females and nymphs. They mostly attach to leaves or to the junction between branches and leaf stalks, sucking the plant's sap. At the affected sites, mild cases form black spots or black patches, while severe cases cause the entire plant to wither and die.

Control methods: 1. Strengthen quarantine: strictly implement the quarantine system and do not introduce seedlings carrying the pest. Do not take scions or cuttings from pest-carrying seedlings.

2. Scientific management: during the growing season, try not to prune heavily. If pruning is necessary for uniform appearance, then after pruning, spray a protective pesticide such as 1500 times mancozeb or 1000 times carbendazim once every 5 to 7 days, for 3 to 4 consecutive sprays. Strengthen routine management, pay attention to ventilation, apply fertilizer reasonably, water scientifically, and enhance tree vigor and disease resistance.

3. Timely observation: frequently inspect for pest activity and check whether white flocculent material appears, so as to detect it early and control it at the right time.

4. Chemical control: pesticide control is effective during the peak egg-hatching period or the first-instar nymph stage. Commonly used are 1000 times jiesha solution or 1000 to 1500 times supusha solution, sprayed once every 5 to 7 days, for 2 to 3 consecutive applications, which can completely eliminate them. When spraying, be sure to spray the whole plant (including diseased plants and healthy plants), and ensure the front and back of leaves are evenly covered with the pesticide. When only a few plants are affected, repeatedly wipe the affected areas with a wet cotton ball soaked in rice vinegar or alcohol, which can thoroughly kill the nymphs with very good results.

5. Protect natural enemies: pay attention to protecting and utilizing the natural enemies of scale insects, such as parasitic wasps, predatory ladybirds, and green lacewings.

6. Eliminate adults: combine winter pruning to eliminate adults and avoid a large outbreak of nymphs the following spring.