There are many plants of the boxwood family, the most common ones are large-leaved boxwood, melon seed boxwood, bird's tongue boxwood, etc., they are not only evergreen in all seasons and very resistant to pruning, and are widely used in landscaping. They can often be seen in road greening, community greening, universities and parks.
In the maintenance process of boxwood, we often see such a phenomenon, that is, the young leaves of boxwood appear large areas of lack of moments, or even dry, careful observation on the boxwood can also find a lot of white spider web-like filaments, and some black-green dot-like substances, what is going on?
The picture shows many white filaments found on boxwood
In fact, this is because these boxwoods have suffered from the harm of the boxwood silk leaf borer!
<h1 class="pgc-h-arrow-right" >What is boxwood leaf borer? </h1>
Pictured is the larvae of the boxwood silk borer
The boxwood leaf borer is actually a pest of the Lepidoptera borer family, which mainly feeds on the young leaves of plants by larvae. Its host plants are relatively few, mainly large-leaved boxwood, melon seed boxwood, bird's tongue boxwood and other boxwood family plants.
<h1 class="pgc-h-arrow-right" > what are those white filaments? </h1>
Pictured is the larvae of the boxwood silk borer
The larvae of the boxwood silk borer are more special when feeding, it will first spit out some filamentous substances from the body to form a nest, wrap the young leaves and itself in the small nest it has built, and then eat in the nest.
The white filaments we see on the branches and leaves of the boxwood are the silks that the boxwood silkworm itself spits.
<h1 class="pgc-h-arrow-right" > what are those black-green punctate substances? </h1>
The picture shows the feces of the larvae of the boxwood silk borer
Many friends think that the black-green punctate substances on the leaves of boxwood are the eggs of the boxwood silkworm borer, which is wrong, because these black-green punctuated substances are actually the feces of the boxwood silk borer.
The eggs of the boxwood silkworm borer are mainly distributed on the back of the leaves, and they are milky white at the beginning of their birth, and slowly turn pale brown before hatching.
Therefore, whether it is from the color or the distribution position, it can be judged that the black-green substances we commonly see on the leaves are not the eggs of the boxwood silkworm borer but the feces.
<h1 class="pgc-h-arrow-right" > Why is it difficult to control boxwood silkworm borer? </h1>
The main reason why the boxwood silkworm borer is not easy to control has a lot to do with its unique hazard mode, mainly from the following aspects:
1. When the harm is carried out, it has a certain suddenness.
We know that the boxwood silk borer overwinters with its young larvae on host plants such as boxwood, and it is not easy to be detected in winter. And these overwintering larvae are actually very sensitive to changes in temperature, the temperature has just risen in the spring, people have not yet started the prevention and control of insect pests in the year, it will begin to bud for harm, and the number of insect mouths is very large, out of the bud can be harmful, with a certain suddenness, so that everyone is caught off guard.
2. It has a certain degree of concealment when it is harmful.
The picture shows the boxwood silk borer harming melon seed boxwood
The larvae of the boxwood silk borer are yellow-green in color, and there are some black spots on the back, which are very similar to the color of the branches and leaves of host plants such as boxwood, so it is difficult to be found when it has just hatched and budded.
When it eats the hazard, it also likes to spit silk nest, carry out harm in the nest, and if it is not carefully observed in the early stage of the hazard, it is difficult to be found by everyone.
When we find that the yellow poplar is missing and dry, the harm is often very serious, and the best prevention and control period is missed.
3. The harm has a certain degree of binge eating.
The picture shows the leaves of boxwood after being harmed by it
The larvae of the boxwood silk borer will enter the binge eating period after 3 years, and the amount of food will be greatly increased, and the plants that are harmed by it may be left with only insect droppings, silk mesh, dry leaves, etc. on the plant within a few days.
Therefore, for the control of the boxwood silk borer, we must seize the critical period of prevention and control, try to control it before its large-scale outbreak and before entering the gluttony period, and reduce its damage to garden plants.
<h1 class= "pgc-h-arrow-right" > so when is the best time for the control of boxwood silkworm borer? </h1>
There are two main periods of optimal control of boxwood silk borer:
One is the budding stage of the overwintering larvae. At this time, the overwintering larvae have just come out of harm, the number of insect mouths is small, and the resistance to drugs is also weak.
The second is the early stage of the first generation of larvae. Because the number of pests in this period is not very large, the young age has not yet entered the binge eating period, and the harm to garden plants is not very large.
< h1 class= "pgc-h-arrow-right" > when exactly is the budding stage of the overwintering larvae? </h1>
The picture shows the larvae in the white silk nest
Yellow poplar silk moth does not occur only one generation a year, the generation difference between the north and south of China is relatively large, for example, in qinghai area only occurs 1 generation a year, and in Shandong, Henan and other places can occur 2 to 3 generations a year, in the south and other areas can even occur 3 to 4 generations a year, generation overlap phenomenon is very serious.
Moreover, due to the large difference in the climate between the north and the south of China, the overwintering larvae of the boxwood silk borer are also different in different regions.
For example, in East China and Central China, there is generally a large-scale bud hazard of overwintering larvae around mid-to-late March every year, while in North China, the overwintering larvae of Boxwood silk borer often begin to bloom in large areas in early April.
Therefore, in the daily management, we must carry out regular inspection and inspection, and prevent and control it in time at the beginning of its bud hazards, so as to achieve early detection and early prevention!
<h1 class="pgc-h-arrow-right" > How to prevent and control boxwood silkworm borer? </h1>
1. Combine pruning to cut off the cocoon of overwintering insects.
Since the boxwood silk borer overwinters with young larvae on the host plant, in order to reduce the source of overwintering insects, it can be combined with winter pruning to cut off those dead branches and leaves with insect buds.
2. Use its nesting habit to remove the nest and pupae.
The picture shows the pupae of the boxwood silk borer before it feathers
Since the larvae of the boxwood silk borer have the characteristics of nesting hazards, the nest can be removed in time during daily inspections, and the pupae are removed in time during its pupal feathering period.
Especially in the early age of the first generation of larvae, it is necessary to pay special attention!
3. Seize the budding period of overwintering larvae and prevent and control it in time.
In early March in the spring, it is necessary to organize staff to regularly inspect the buds of overwintering pests on boxwood plants, and once it is found that the overwintering larvae of the boxwood silk borer begin to bud harm, it is necessary to select drugs in time for prevention and control.
In the treatment of pharmaceuticals, you can choose patoprethroids and some systemic insecticides for control, continuous spraying 2 to 3 times, each interval of 7 to 10 days, you can achieve a comparative control effect.
When other agents are not ideal, some microcapsule suspension type insecticides can also be selected for control.
4. Use the phototropism of adult insects to carry out light booby traps.
The picture shows the adult of the boxwood silk borer
Generally speaking, the first generation of adults of the boxwood silk borer appears in mid-to-late May. We can take advantage of the phototropism of adult insects and use black lights to booby trap light in places where boxwood is more planted.
It is important to note here:
The adults of the boxwood silkworm have the characteristics of diurnal and nocturnal, and if you want to use drugs to control its adults, the spraying time is best chosen in the evening.
Well, about the prevention and control methods of boxwood silkworm borer, I will briefly share it with you here today.
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