Slugs are common mollusks in rubber plantations and have not been significantly harmful to rubber production. However, since May this year, slugs have occurred seriously in The slugs in the agricultural reclamation areas of Zhanjiang Agricultural Reclamation and Maoming Agricultural Reclamation in Guangdong Province, and the harm caused by localized slugs has seriously affected normal rubber tapping production, and the losses have been serious. At present, there is a lack of research on the harm and control of slugs on rubber at home and abroad, and the production is mainly based on the traditional control methods used by other crops and the technology initially developed by the natural rubber industry technology system insect pest control technology team to implement control. The main production areas should attach great importance to carrying out research on the harm of rubber tree slugs to reduce their impact on rubber production.
First, the type, distribution and hazards of rubber tree slugs
Variety and identification
The slugs that currently harm rubber trees have been identified as Philomycus bilineatus of the two-line mucophilic slugs. Slugs are harmful mollusks that harm a variety of vegetables, flowers, strawberries, crops, edible fungi, etc. Its adult body is bare, soft and shellless, with a wide front end, a narrow and long posterior end, and a crest-like protrusion at the tail. The body is off-white or pale yellowish brown , with a longitudinal band of black spots in the center of the back , and a longitudinal band on each side of the body. Adult stretches 40–70 mm in length and 11–12 mm in width. The antennae are two pairs, the first pair is short and the back pair is long. The breathing holes are round, about 5 mm from the head on the right side of the body, and a ribbon on the right side bypasses the breathing holes from below. The puddles are white and the tendons secrete a large amount of mucus. The larvae are similar to adults and are smaller. The eggs are oval, colloidal, translucent, shiny, and have mucus outside the eggs that stick the eggs together.
Distribution and hazards
Double-line mucinous slugs are widely distributed in China, shanghai, Jiangsu, Zhejiang, Hunan, Guangxi, Guangdong, Yunnan, Sichuan, Guizhou, Henan, Xinjiang, Beijing, Hainan, Fujian, Anhui, Taiwan and other provinces and regions. The two-line mucinous slug not only eats the stems, leaves, fruits or juices of crops in adults or juveniles, causing direct economic losses, but also secretes mucus and excretes feces to contaminate fruits and vegetables, resulting in a decline in the market price of products.
Occurrence and hazards on rubber trees
For a long time, slugs have been found on rubber trees in Yunnan, Hainan, Guangdong and other provinces, but there has been no outbreak.
Recently, slugs have been found to be harmful to rubber production in the rubber planting area of Guangdong Agricultural Reclamation, and the degree of harm has gradually increased. After investigation, in the occurrence of harmful rubber gardens, the number of slugs per gum tree is generally more than a dozen, and the number of more than 600 is more than 600. The harm of slugs to gum trees is first of all, adults and juveniles gather on the gum tree cutter or in the gum cup to suck the latex, which is dense on the cut line can seriously cause the outflow of latex, resulting in serious yield loss; Second, the excrement and mucus secreted by slugs affect the cleanliness of the glue; Third, slugs densely packed on the cutting surface and rubber cup will affect the rubber workers' tapping and rubber collection work, reducing work efficiency, and individual glue workers will have a dense phobia when they see dense slugs.
According to statistics, this year, the area of slugs affected by slugs in Zhanjiang Nongken Changshan Farm and Dongsheng Farm in Guangdong Province alone is more than 3,400 mu. Among them, the heavy hazard of Changshan Farm (the number of slugs is more than 100 heads/plant) covers an area of more than 800 mu, causing a daily reduction in dry rubber production of more than 450 kg. At present, in the local serious area, each tree position (400-500 trees) cutting 1 knife glue only harvests more than 10 kilograms of glue, which seriously hits the enthusiasm of rubber workers.
II. Recommendations for Response and Prevention
Do a good job of investigation and monitoring, and grasp the dynamics of occurrence
Combined with the production of tapping, a survey of the occurrence of slugs is carried out every 10-15 days in the area where slugs are common, so as to grasp the occurrence of slugs in a timely manner and provide data support for prevention and control. The survey adopted a five-point sampling method, and 5 survey points were taken in the survey area according to east, south, west, north and middle, and 5 trees were randomly selected at each point for quantitative investigation; The survey time was 6:00-7:00 on 1-2 days after rain, and the survey site was within 160 cm of the head of the tree to the trunk and within 20 cm of the tree disc around the head of the tree; The survey included the number of slugs and their distribution on trees or discs.
Take a variety of measures to control slugs in an emergency manner
In view of the current serious situation of slugs, a variety of measures such as chemical prevention and control, lime barrier touch killing can be taken for emergency control. Chemical control can choose to use spiridine wettable powder or tetraacetaldehyde granules and other agents. Spiroxamine is a strong molluskic agent, using spray or irrigation method to administer the drug, slugs once in contact with or smoked, has a good quick effect; Tetraacetaldehyde is a new type of pesticide that has a long shelf life, but a slightly less rapid-acting effect.
In view of the fact that the survey found that when the ground was relatively wet 1-2 days after rain, during the period of 14:00-19:00, more than 90% of the slugs were distributed on the ground, soil and dead branches and leaves within 20 cm of the rubber tree head, therefore, the recommended application method of spiride was to spray slugs on the dense parts of slugs such as the head of the tree, within 20 cm of the tree disc and the trunk with 30 times of the liquid (or to irrigate the head of the tree and the tree disc within 20 cm), and the application time was 14:0 0 for 1-2 days after rain 0-19:00; tetraacetaldehyde granules are applied all day after 1-2 days after rain when the ground is wet, and the sprinkling area is within 20 cm of the tree disc.
In addition, quicklime can be sprinkled within 20 cm of gum tree head and tree disc to physically block and touch kill slugs.
Carry out technology research and development to solve the problem of sustainable control
Although the two-line mucinous slugs have existed for a long time in the planting area, there has been no outbreak of disaster, and no targeted prevention and control basic and technical research has been carried out in China, and the occurrence characteristics are unknown and the prevention and control technology is lacking. Therefore, there is an urgent need to carry out the following research work: (1) basic biological observation of slugs to identify weak links in control; (2) Screening of prevention and control agents, avoidants, and enticing substances to provide safe and effective inputs for prevention and control; (3) Research and integration of key technologies for prevention and control, solve the key technologies for the use of drugs such as poisoning and avoidant enticing, and integrate comprehensive technologies for the prevention and control of rubber tree slugs, including intervention in habitat and breeding sites, migration barrier, adult and juvenile poisoning.
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Source: Hainan Agricultural Technology
Editor: Haikou Municipal Bureau of Agriculture and Rural Affairs
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