How to control the citrus mealybug? These methods are simple and effective
The citrus mealybug is an insect of the family Pseudococcidae in the order Homoptera. In addition to citrus, its host plants include grape, longan, lychee, wampee, avocado, sugar apple, jujube, tea, mulberry and so on. The nymphs and adults pierce and suck the sap of branches and leaves; in severe cases the leaves dry up and curl, weakening the tree's vigor or even causing it to die, resulting in dead shoots and fruit drop in fruit trees and affecting their economic value. Let's take a look below at what pesticides are used for the citrus mealybug!
Living habits of the citrus mealybug
In South China it produces 5 to 6 generations a year, overwintering as nymphs and female adults in bark crevices on branches and in curled leaves. It begins activity in February of the following year, and lays eggs in egg sacs in late March; each female can lay 200 to 500 eggs, and after hatching the nymphs gradually disperse and move about to cause damage. The peak occurrence periods of nymphs for each generation are early April, mid-May, mid-July, mid-September, early October, and mid-November, with the highest population density and the most severe damage in April to May and September to November, and generations overlap. Males are generally very few in number, and reproduction is mainly parthenogenetic.
Damage characteristics of the citrus mealybug
In Guangzhou the citrus mealybug occurs 5 to 6 generations a year, overwintering as nymphs and adults in cracks or holes in the trunk and branches and in curled leaves. It begins activity in early February, mainly damaging spring shoots, and the first-generation egg sacs appear around late March. Nymphs and female adults mostly gather in groups on tender shoots, fruit stalks and the fruit base to cause damage, followed by leaf stalks and small branches. Among these, the adults and nymphs of the first and second generations mainly damage the fruit, while the third to sixth generations mainly damage autumn shoots. Throughout the year the population density is highest in April to May and October to November.
How to control the citrus mealybug?
1. Agricultural control: Strengthen orchard cultivation and management. In combination with spring flower and fruit thinning of longan and pruning after fruit harvest and before spring shoots sprout, cut off overly dense shoots and insect-infested branches and burn them in a centralized manner, so that the canopy is ventilated and light penetrates, humidity is reduced, sources of insects are decreased, and damage is lessened. At the same time, control the sprouting of winter shoots on longan, which can not only prevent massive consumption of the tree's nutrients that would affect flowering and fruiting the following year, but also cut off the pest's food source, thereby reducing the population base.
2. Biological control: Raise pheasants in the orchard. During the adult and nymph stages of the citrus mealybug, the pests on longan trees can be brushed off by hand to fall to the ground for the chickens to eat; during the nymph stage of the lawana wax cicada, they often jump to the ground when startled and become good feed for the chickens, and during the peak emergence period of adults they can be caught with nets. At the same time, attention should be paid to protecting and utilizing predatory and parasitic natural enemies, using pesticides rationally, and not using pesticides that are highly harmful to natural enemies.
3. Chemical control: Based on the characteristic that the lawana wax cicada and the citrus mealybug, at the newly hatched nymph stage before feeding, have no waxy powder or secretions on their bodies and are relatively sensitive to pesticides, grasp the peak period of newly hatched nymphs and spray pesticide at the right time. For the citrus mealybug, control should focus on the spring shoot period. You can choose 80% dichlorvos 1000-fold solution or 90% crystalline trichlorfon 1000-fold solution plus 0.2% laundry detergent, once every 5 to 7 days, for a total of 2 sprays; you can also choose 48% chlorpyrifos emulsifiable concentrate 1000-fold solution, 18% bisultap aqueous solution 400-600-fold solution, or 50% monosultap wettable powder 600-fold solution for control.