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Citrus fruit serving
Ticks are common in the southern region and more difficult to prevent insect pests, it has many species, rapid reproduction, generation overlap, although the degree of pest is not as good as red spiders, wood lice and other pests, but also a citrus management process can not be ignored, due to improper control and caused by the phenomenon of yield reduction occurs every year.
There are many kinds of shell insects on citrus, common ones are blowing sponge borer, Kang's mealybug, yascanth, bran flake borer, brown roundworm, red wax bug and so on.
Blowing sponge borer: the male adult is thinner, the female adult is oval, orange-red, and has short black hairs on the surface of the body. The back is covered with white wax powder. After maturity, a white oocyst is formed behind it, and the egg sacs are connected into a single obvious longitudinal groove of about 15 stripes.
The first generation of eggs and nymphs peaks in late April to June, and the second generation of nymphs occurs from August to September.
Kang's mealybug: male adults are purple-brown with a pair of transparent wings; female adults are oval, relatively flattened, covered with white wax powder, with 17 pairs of white wax spines on the body margin, and 1 pair at the end of the abdomen is almost equal to the body length.
The first generation of nymphs occurs in mid to late May, the second generation in mid- and late July, and the third generation in late August.
Sagittal insect: the male insect bug shell is narrow and elongated, orange-yellow, with transparent wings; the female adult insect shell is arrow-shaped, the anterior tip is wide, there is a longitudinal ridge in the center, 2 to 4 mm long, yellowish brown to tan, and the edge is grayish white.
The prime period of the young worms: the 2nd ward, the early May, the mid-August 3rd ward, the middle of July, the middle of September;
Bran flap borer: the male is narrow and long, the shell of the moth is off-white or grayish brown; the female is lilac, nearly round or oval, the shape and color of the moth shell resemble a bran shell, and the edges are extremely uneven.
There are three relative peak periods in the year, which occur from late May to early June, late July to early August, and early to mid-September.
Brown roundworm: male adult insect shell purple-brown, the edge part is white or off-white, oblong oval, the posterior end is elongated, about 0.7 mm wide; the female adult insect shell is round, purple-brown, light brown at the edge, central bulge, shell point in the center, umbilical, yellowish brown or full yellow in color. The shell is about 2 mm in diameter.
The first hatching and young worm flourish period 1st mid-May;
Red wax bug: Male adult body dark red, a pair of forewings, white translucent; female adult oval, back covered with a thick dark red to purple red wax shell, the wax shell at the top of the concave umbilical shape. There are 4 white wax bands rolled from the ventral surface to the back.
In most areas, one generation occurs a year, and the egg hatching peaks from late May to mid-June.
1. Harmful symptoms
The insects are small, dense and very harmful, and they all cause harm to citrus by sucking sap with a stinging mouthpart. Such as blowing sponge bugs, nymphs and female insects harm the trunk, branches, leaves, etc., can induce serious bituminous coal disease, so that the tree weakens, branches and leaves fall, and even the whole plant dies.
Yasukite, bran flap, etc. are endangered by adult insects and juvenile ants on citrus branches, leaves and fruits. After the damage, the branches wither, the leaves curl and dry, and easily fall off, resulting in the decline of the tree, the fruit remains in a green state, the quality deteriorates, and the yield decreases.
Second, the difficulty of prevention and control
1, large reproduction
In addition to sexual reproduction, the insects can also reproduce as parthenogenes. The amount of reproduction is large, more than 90% of the eggs laid can develop, some occur in 1 generation per year, the high can reach 3 to 4 generations, in 1 year and 2 generations to calculate, 1 tick, 1 year reproduction of up to 90,000.
2. Generational overlap
Most species of insect shell insects can occur in multiple generations per year, and the middle and late generations overlap, and the control is more difficult when the population base of the insect is large.
3. Strong resistance
The newly hatched nymphs have poor resistance, but after 2 years of age, the insect body will be coated with thick wax, which has a protective effect on the insects, and the resistance to the insects is greatly enhanced. Therefore, we must seize the critical period of nymph incubation for spray control.
4. Concealed
The insect is small in size and has hidden habits, and after finding a suitable place, it will pierce the mouthpart into the plant to absorb the sap and begin to live a fixed life, if not carefully examined, it is usually too late to find.
Third, prevention and control methods
1. Clear the garden in winter to reduce the source of insects
The dry branches on the tree and the branches and leaves with too many insect mouths are pruned, and when the insect mouth is small, it can be peeled off by hand, brushed off, and the bamboo pieces scrape out the overwintering insect body, burned centrally, and then carefully spray mineral oil + chlorpyrifos or pine alkali mixture to the branches and leaves of the canopy 1 to 2 times to reduce the base of the overwintering insect mouth.
2. Seize the critical period and choose drugs for prevention and treatment
From mid-May to mid-June every year, it is the nymph period of most insects, and it is also the best time for control, be sure to seize it, stop spraying too early or start spraying too late, will affect the control effect.
According to the morphological characteristics of each insect shell insect, the insect situation should be observed frequently from May to June, which is the period of citrus summer shoot extraction, and it is also the second physiological peak of citrus fruit drop to the growth period of young fruits, and the drug control can effectively suppress the insect mouth base and prevent the harm of the first generation of young oysters from fruiting and new shoots.
Agents can be selected from chlorpyrifos, ethyl spironium, thiazide, thiamethoxazine, flufenacil, matrine and the like.
When spraying, it must be even and thoughtful, and the branches, foliage, leaf back, petiole, and fruit stem should be sprayed evenly to improve the control effect. If there is rain within 48 hours after spraying, it must be sprayed in time.
3. Improve the cultivation environment and protect and utilize natural enemies
(1) Enhance tree potential, improve insect resistance, management attention to strengthen fertilizer management, increase fertilizer containing organic matter, balance tree nutrition, stimulate plant growth; at the same time, reasonable pruning, open the "skylight", increase the light in the canopy, enhance tree potential, improve insect resistance.
(2) Promote the cultivation of raw grass, plant crops such as green manure inside and outside citrus orchards, realize biodiversity, and create a good environment for the survival and reproduction of natural predators such as ladybirds and small bees.
(3) Control the late medication, the natural enemies of the tick are jumping wasps, aphid wasps, golden wasps and other parasitic wasps. These parasitic wasps occur in large amounts in autumn, so they should not apply pesticides or less in autumn, pay attention to the selection of high-efficiency and low-toxicity insecticides, and reduce the number of sprays as much as possible to give full play to the role of natural enemies.