Nowadays, it is the formation period of young fruits after plum blossoms and leaves, and fruit farmers are faced with many challenges in production, one of the most difficult problems is the attack of plum heartworms on young fruits.
These tiny plum heart-eating pests silently erode the young plum fruits, causing considerable economic losses to the growers.
Picture 01~02): Plum bee larvae burrow young fruits
In this issue, Qingjiang Crane will focus on and chat with all the teachers about the related topics of plum "heartworm", aiming to focus on keywords such as "plum young fruit formation period", "heartworm harm", "plum heartworm", "almond bee", "apricot weevil" and other keywords, discuss in detail how to judge that plum heartworm has been bored into the fruit, and put forward efficient planting prevention and control strategies. I hope it will be helpful to you, and actively participate in the interactive comments, forward and share the pictures and texts of this issue.
Symptoms of heartworm harm to young plum fruits:
The formation period of young plum fruit is the key period for fruit growth and development, and it is also the most active period for plum heartworm.
Picture 03~04): Mothed from the plum suture
Pests such as heartworms, almond bees, and apricot weevils, with their unique way of life, live "parasitic" and "semi-parasitic" inside and outside plum fruits, which seriously destroys the normal growth and reproduction of fruits. These heartworms will not only cause the quality of the fruit to deteriorate (appearance and edible value), but also cause the early fall of plum fruit, which will reduce the yield and planting efficiency.
Therefore, the prevention and control of heart-eating insects is crucial.
How to tell if a plum heartworm has eaten inside the fruit:
To determine whether a plum heartworm has penetrated the flesh of a fruit, growers can tell by looking at the appearance and internal changes of the fruit.
Picture 05~06): "Living" heart-eating worm
Generally speaking, the surface of the fruit infested by the plum heartworm will have depressions or wormholes, and there will be insect feces or insect passages inside the fruit, and there are "clues" of the heartworm drilling on the surface of the fruit.
It is really impossible to inspect, and you can directly observe whether there are insects by cutting open the fruit. Although these methods are simple and easy to implement, they require extensive experience and careful observation by the grower.
With the "basic" rules for plum heartworms to burrow young fruits, when common plum fruits are harmed by "heartworms", different types of "heartworms" will also form special "traces" on the surface of plum fruits.
Through these "clues", we can accurately find out whether the plum "heartworm" has burrowed into the inside of the fruit:
Picture 07~08): Heart-eating insects that are still active in the nuts
01) Identification and diagnosis method of weevil "heartworm" borrowing plum young fruit:
Weevils eat the young fruits of plums, mainly adults. Adults move on the plum branches from 8 a.m. to 4 p.m. (this time period) to find a target (the best active period is around 11 a.m. to 2 p.m.), which is what we call the young plum fruit, ready to lay eggs.
After finding the target, the adult weevil bites the stalk of the young plum and lays eggs. If you just gnaw on the plum stalk, it will not cause early fruit drop, but sooner or later it will also form. Sometimes, the adult weevil directly bites off the stalk of the young plum fruit, causing the young fruit to fall off directly.
To lay eggs, the adult weevil first bites a small hole in the young fruit, then lays the eggs in the hole, and then covers the hole with mucus. "Black spots" form at the end of the wound, and neither the adult nor the larvae enter the kernel or flesh of the young fruit.
Picture 09~10): There is a glue flow phenomenon at the cavity
02) Identification and diagnosis characteristics of larvae of "kernel bee" larvae harming young plum fruits:
The larvae of the "kernel bee" species harm the young plum fruit in the "physiological" fruit drop period after the plum flowering. Some fruit farmers call "kernel bees" plum bees.
The larvae of the "kernel bee" burrow the young plum from the "suture" of the young plum fruit and enter the pit or pulp. When the damage is most serious, the larvae of "kernel bees" can eat the kernel part of the young plum fruit, causing a large number of plum fruit drops.
03) Identification and diagnosis characteristics of "small codling moth" larvae heart-eating insects burrowing plum larvae:
The heart-eating insect of the "silverfish moth" is actually a larvae of a codling moth, and its harmful feature on the young plum fruit is that it borers into the fruit from the "base of the fruit peduncle" of the young plum fruit. Multiple generations (at least 3 generations) can occur in a year, with the first generation of larvae being the main victim.
Picture 11~12): Plum branches and leaves after rain
After hatching, the larvae of the first generation of silverfish moth larvae crawl on the surface of the young fruit for a while, and then begin to bury the fruit into the fruit until it is "unhardened". The victim then sheds the main branch.
Because the young fruit is not fully developed and the flesh is not much, the first generation of codling moth heartworms that harm the young plum fruit will have the characteristics of "fruit turning harm". Each small larval heart-eating insect basically harms 2~3 young fruits (must be carefully controlled).
However, after the second generation, the young heartworms of codling moths have lost the habit of "turning fruits". The damaged fruit often appears "flowing gum" and hangs on the tree, which is either yellow and early, or distorted and uneatable.
Efficient prevention and control strategies of plum heartworm in the young fruit stage:
Picture 13~14): plum branches and leaves after medicine
In view of the damage of heart-eating insects during the formation period of young plum fruits, fruit farmers should adopt comprehensive prevention and control strategies to reduce the occurrence and spread of pests at the source.
First of all, it is necessary to strengthen orchard management, regularly clean up weeds and dead branches and leaves in the orchard, and reduce the habitat of pests.
Secondly, it is necessary to apply fertilizer and water reasonably to improve the disease resistance of fruit trees. At the same time, biological control methods, such as the introduction of natural enemy insects or the spraying of biopesticides, can also be used to effectively control the population of heart-eating insects.
In addition to the above-mentioned measures, farmers can also use physical and chemical control methods. For example, insect traps such as yellow boards or black lights are set up in orchards to attract and kill pests, and high-efficiency and low-toxicity chemical pesticides are sprayed to quickly kill pests during the peak occurrence of heart-eating insects. However, it should be noted that the use of chemical pesticides should be strictly controlled in amount and frequency to avoid pollution and residues to the environment and fruits.
Picture 15~16): Young plum fruit at the bulging stage
The commonly used chemical agents and concentrations of plum heartworms are: 15.6 avermectin butyl ether urea emulsifiable concentrate 1000~1500 times, or 45.5% avermectin butyletherurea suspension 2000~3000 times, or 5% avermectin acetamiprid emulsifiable concentrate 2000~2500 times, or 5% fipronidine emulsifiable concentrate 2000~3000 times, or 6% avermectin chlorantraniliprole suspension 2000~2500 times, or 5.2% avermectin perchlorine emulsifiable concentrate 800~1000 times liquid, or 1.8% avermectin deltamethrin emulsifiable concentrate 800~1000 times, or 20.4% avermectin pyrethuron suspension 2000~4000 times liquid spray stem and leaf treatment.
Summary and prospect of comprehensive prevention and control of plum heartworm:
Heart-eating insects in the formation period of young plum fruits are a major problem faced by fruit farmers, but through scientific prevention and control strategies and effective management methods, the damage of pests can be completely reduced.
Picture 17~18): Young plum fruit at the bulging stage
In the future, with the continuous progress of agricultural technology and the accumulation of planting experience of fruit farmers, I believe that we will be able to better cope with the challenges of heart-eating insects and other pests and achieve high yield and high quality of plums.
In short, in view of the damage of heartworms in the formation period of young plum fruits, fruit farmers should adopt comprehensive prevention and control strategies to ensure the healthy growth of fruits and the improvement of yield and quality from multiple aspects. At the same time, it is also necessary to continuously learn and explore new plum heartworm control technologies and methods to adapt to the changing market demand and ecological environment.
Picture 19~20): Young plum fruit at the bulging stage