<h1>Overview of Orangery Lurkers</h1>
TV dramas often stage spy movies, in which the lurkers are haunted; and in real life, there is also such a role in our orchard, that is, a small insect that plays "lurking" in the orchard all the time, seemingly weak, but in fact it is very harmful.
Since May, the leafminer moth in the citrus orchard has begun to become active, and the harmful symptoms are obvious, and the young leaves are rolled up, forming a white curved insect path, making the leaves curled, hardened, easy to fall off, and the growth of new shoots is not full.
If you look closely, you can see that there are almost transparent white insects under the surface of the leaves, which is a very famous pest in citrus cultivation - citrus leafminer moth.
Because it is good at "lurking", this insect is difficult to kill, harming citrus leaves, causing the affected leaves to shrink, easy to fall off, and induce the occurrence of ulcer disease. The damaged leaves have an unsightly pattern on them, which are figuratively called "ghost drawing symbols" by farmers, and leafminer moths are also called "drawing insects".
The life of the leafminer moth is only about 20 days, going through four stages of eggs, larvae, pupae, and adult insects, in this short "insect life", the larvae of the leafminer moth will dive under the leaf epidermis, eat the leaf flesh inside, and gradually form a curved worm path while eating.
The soft young leaves are the "cake" of the leafminer moth larvae, the food is abundant, because of the protection of the epidermis, pesticides, rain can not help it. So this soft little bug can eat white and fat, and then "break the cocoon into a butterfly" to harm more citrus trees.
It's a hot, rainy summer season, with citrus shoots pumping quickly, fresh foliage and suitable climatic conditions that make pests want to move.
Tips: Your "friend-damaged" leafminer moth is now online!
<h1>Meet the leafminer moth</h1>
1. Leafminer moth - adult
▲Leafminer moth - adult
The adults are about 2 mm long , with silvery-white wings and filamentous antennae. The forewings are pointed leaf-shaped with long marginal hairs; the base of the wing has two longitudinal stripes of black brown with a "Y" shape at about 2/3 of the wings; and the marginal hairs near the tip of the wings form a black round spot.
2. Leafminer moth - egg
▲ Leafminer moth - egg
The eggs are very small, 0.30 to 0.36 mm long, oval, flat, white and transparent, usually on the back of the leaf and near the midrib of the young leaf. (Can't see clearly, you can click on the picture to see the big picture, there are several eggs in the center more obvious)
3. Leafminer moth - larvae
The larvae are 0.5 mm long and pale yellow when they first hatch, and the 1st and 2nd thorax is enlarged, almost square, and the tail tip is thin.
When mature, the body is 4 mm long, flattened, long spindle-shaped, yellow-green; the head is pointed; the thorax and abdomen are 13 segments, and there are 4 concave holes neatly arranged on both sides of the dorsal line of each segment; the foot is degenerated; the ventral end is thin, with a pair of long tails.
4. Leafminer moth - pupae
▲ Leafminer moth - pupae
The pupa is about 2.8 mm long, spindle-shaped, initially pale yellowish, then yellowish brown to dark brown, with an inverted T-shaped structure on the top of the head, antennae, feet and body separation, and a distinct fleshy spine on each side of the posterior margin of the terminal segment.
<h1>Leafminer moth harmful symptoms</h1>
▲ Leafminer moth pest symptom - ghost drawing symbol
It is mainly harmful to the new shoots, shoots and shoots of citrus fruit trees, and the larvae sneak under the epidermis of the young leaves of citrus to feed.
▲A silvery-white tunnel that forms a curved and curved one
A curved silver-white tunnel is formed, with insect feces left in the road, forming a black line in the center, and the leaves are seriously curled, hardened and easy to fall off after being killed.
▲The growth of new shoots is not full
The growth of new shoots is not full, affecting the tree potential and flowering and fruiting in the next year, and it is easy to fall off. A small number of victim fruits are perishable, which directly affects yield and quality!
▲Wounds caused by damage on the leaves often induce the spread of ulcer disease
Wounds on the leaves often induce the spread of canker disease. The curly leaves of the victims often become the overwintering and settlement places of pests such as red spiders, which increases the difficulty of winter control.
<h1>Characteristics and regularities of occurrence</h1>
1. Occurrence characteristics
Citrus leafminer moths are, in order of severity to severity: adult trees< young fruit trees< nurseries, early autumn shoots< summer shoots< late autumn shoots. The main reason is that the summer and autumn shoots of seedlings and young trees are more uneven, which is suitable for adult leafminer moths to lay eggs and larvae as pests, so it is more seriously affected than adult trees.
2. Occurrence law
Occurs 8 to 15 generations a year, overlapping generations, mostly overwintering with larvae and pupae, and about 10 days after the adult and egg bloom, which is the peak of larvals.
Generally, the average temperature from early May to early June is about 20 °C, and the larvae begin to occur. The insect population increases rapidly in late June, and from July to August, it is the most frequent and harmful period of the year. After October, the harm gradually decreased.
When the new shoots begin to twitch, the citrus leafminer moth occurs; the branches elongate rapidly, and the citrus leafminer moth quickly hatches from the eggs to become larvae; the branches stop elongating, and the larvae begin to pupate and feather.
The branches are long and long, and the life period of the citrus leafminer moth is correspondingly prolonged, and vice versa, it is short. However, the length of life of citrus leafminer moths is still dominated by temperature.
<h1>Key technologies for prevention and control</h1>
Although the citrus leafminer moth has a short life, it is very harmful, and the leafminer moth can occur about 10 generations per year, overwintering on the affected leaves with pupae and larvae. From late April to early May, the larvae begin to harm, and July to September is the peak of the occurrence period, and the harm is also serious. Decrease occurs after October.
A generation of more than 20 days. Adults mostly feather in the early morning, inhabit the leaf back and weeds during the day, are active at night, and are phototropic. Eggs are laid in the evening of the second to third day after mating, and the eggs are mostly laid near the midrib on the back of the young leaves, and can be produced several grains per leaf. Each female can lay 40-90 eggs, with an average of about 60 eggs.
After the larva hatches, it sneaks under the leaf epidermis from the bottom surface of the egg, eats the leaf flesh inside, and advances while eating, gradually forming a curved worm path. When ripe, most of them moth to the leaf margin, in which the insect body spits a thin cocoon to pupate, often causing the leaf edge to curl up. Seedlings and young trees, due to the large number of shoots and not neat, are suitable for adult egg laying and larval damage, and are often more seriously affected than adult trees.
The optimal temperature for the propagation of citrus leafminer moths is 24 to 28 °C, and the relative humidity is about 80%. After the larvae harm the young leaves and young branches, the leaves are curled and hard and brittle and fall off, the growth of the new shoots is hindered, affecting the tree posture and the results of the shoots, and the wounds of the larvae are conducive to the invasion of diseases and insect pests such as canker diseases and mites.
1. Grasp the insect situation and unify the release
Doing a good job in forecasting and forecasting, and mastering the unified release of adult insects during the low peak period is the key to prevention and control. Mastering the insect situation can reduce the number of sprays and avoid the frequent use of pesticides in large quantities, resulting in leafminer moths developing resistance and killing predators by mistake, causing pests to become rampant again. It can be done by observing the top 5 leaves of the new shoots, and when a significant decrease in the number of eggs or young larvae is found, the last shoot is wiped clean and the shoots are released uniformly.
2. Wipe the ends
Leafminer moths can not feed on the mature tips and leaves, and if there are no young leaves, most larvae cannot survive, which naturally reduces the occurrence of leafminer moths.
Summer shoots drawn in June are likely to exacerbate the second physiological fruit fall of citrus and are conducive to the occurrence of leafminer moths, so they should be erased when they are young.
Long summer shoots, long branches and large leaves, not easy to enrich, the following year more do not flower, continue to grow easy to disturb the shape of the tree, except for special circumstances, generally do not retain.
The summer shoots that are drawn in July have a more abundant growth, and can flower and bear fruit the following year and can produce stronger spring shoots, and later form backbone branches that can be retained.
Late autumn shoots that occur after September, due to low temperatures and incomplete growth of branches and leaves, are not conducive to the formation of flower buds, and are susceptible to frost damage, have little use value in production, and provide a food source for leafminer moths, so they should be erased as soon as possible.
4. Protect and utilize predators
Pay attention to the protection and utilization of natural enemies of citrus leafminer moths such as grass ridge, white star bee and predatory ants, because natural enemies such as parasitic bees are mostly feathered in the morning, so the spraying time is best selected in the afternoon or evening. At the same time, attention should also be paid to the use of low-toxicity and low-residue pesticides.
5. Winter Garden
The characteristics of leafminer moths curling and overwintering on the edges of the affected leaves with larvae or pupae, combined pruning in winter or early spring, remove the affected leaves on the autumn shoots (especially the late autumn shoots), concentrate on deep burial or burn, reduce the source of overwintering insects in the following year, and reduce the population base of insects in the next year.
6. Chemical control
Chemical control is still a necessary means of pest control and maintenance. It is particularly important to choose the best time to spray the shoots, and different methods should be taken for different tree ages in production.
In that year, grafted seedlings or rootstock seedlings should be controlled after the new shoots are extracted; the seedling retention period of young trees begins to be applied when the buds grow 0.5 to 1 cm or the damage rate of young leaves reaches 5% or the germination rate of young shoots in the field reaches 25%. Once a time in the next 5 to 7 days, 2 to 3 times in a row, focusing on spraying the canopy periphery and young shoots.
Spraying at the peak of larval hatching after the release of the shoots is the optimal period. The first drug was mainly used to control adult insects. Spray control when summer and autumn shoots grow to 3 mm or when 50% of the new shoots are extracted; spray 2 to 3 times in the evening, every 6 to 7 days, until the new shoots are lignified.
The second drug, mainly to control the young larvae in the leaves of the latent people, can generally be sprayed at noon with better effect.
7. Important tips for the prevention and control of leafminer moths:
For leafminer moths, it is necessary to take medicine to prevent the discovery of the worm path, especially when the orange is released, if it is endangered, it may cause a large outbreak of ulcer disease.
First of all, we must pay attention to the harm of leafminer moths and do a good job in the prevention and control of each round of new and slightly tender leaf stages. Without young leaves, most larvae cannot survive, naturally reducing the occurrence of leafminer moths.
Secondly, conditionally, it is necessary to smear the buds and release the shoots uniformly. Remove sporadic late summer shoots and early autumn shoots. Feeding enough nutrients when the shoots are placed to promote neat withdrawal, cut off the food chain of pests, and shorten the time that pests can be harmed.
Third, in winter, the garden can be cut off and burned by the harmful branches and leaves on the autumn shoots (especially the late autumn shoots), reducing the source of overwintering insects in the following year and reducing the amount of insects in the next year.
Then, pay attention to the protection and utilization of natural predators of citrus leafminer moths such as grass ridges, white star wasps and predatory ants.
Finally, in the use of drugs, long-lasting insecticides such as Thuringiensis, chlorhex benzamide, thiotiazide, thioxazine, thiazepamine can be preferred... Preferential use of long-lasting dosage forms such as microcapsulation dosage forms; systemic + touch-killing compound formulations are preferred.
<h1>Recommended effective drug formulations:</h1>
Chlorofluoride. 2000 times thiamethoxazine;
Chlorofluoride. Thiamethoxamine 2000 times;
5% chlorofluorocyanide 2000 times ten 5% acetamidine 2000 times;
1% methoxylamine avi 1500 times 1500 times 125% thiamethoxazine 2000 times;
20% methymethrin 2000 times 110% pyromyra. Imidacloprid 1500 times.
In addition, butyl sulfur, fly amine, insecticide and other drugs can also be used for prevention and control.
-------------------- dividing line--------------------
Promote citrus rooting, explosive rooting, improve physiological yellowing of the weapon - cool to the end ®
To purchase, please click on the blue text below "Learn More"