Strawberry Red Spider Pest Source: relien
Red spiders are important pests of strawberries, often occurring during the flowering and fruiting period, which is a great threat to the quality and yield of strawberries. In the shed, due to the suitable environment, there are fewer natural enemies, and it is the hardest hit area of the red spider.
In fact, what we call the red spider is a type of pest mite on strawberries, mainly containing red and yellow-white types.
Red type
Cinnabar leaf mite Image source: wikipedia
Rare, occasional occurrence, mainly including truncated leaf mites, cinnabar leaf mites, and Kamize leaf mites.
Yellow-white type
Diplodocus image source: wikipedia
More common, the main pest mites on strawberries, in the case of sufficient food, often appear as green, when there is insufficient food, it is yellow or white, so we often say that yellow spiders and white spiders refer to the two-spotted leaf mites.
Red spiders are usually harmed by adult mites, nymphs that dorsal spike in strawberry leaves to suck sap, spit silk, knot webs, lay eggs, and spawn.
Leaf damage symptoms Image source: Jinzhou Li Yajun
The affected leaves first appear yellow-white to off-white spots from the sides of the main vein of the petiole on the back of the leaf, and the leaves become pale gray and the leaf surface becomes yellow and green.
Red spiders are seriously harmful Image source: qxy0876
When the damage is severe, the leaves are rusty and dry, resembling fire, and the affected plants dwarf and prematurely age, and grow slowly.
Calyx symptoms Image source: Wahaha
During the flowering period, the fruit is reduced and hard, and the deformed fruit is increased, which seriously affects the yield and quality of strawberry fresh fruit, and even the harvest is not harvested.
The red spider on the strawberry is difficult to fight, I think all the farmers are deeply touched, let's analyze why the red spider always can't die?
First, the pest mites themselves have the characteristics of small individuals, rapid reproduction, strong adaptability and easy resistance, which is the main reason why they have jumped into important pests in recent years.
Second, red spiders are mostly harmful to the back of strawberry leaves, which is easy to be ignored, and at the same time, when the drug is prevented, the leaf back is basically unstoppable without penetrating.
Third, a large number of red spiders spit silk knotted webs can protect against pesticides and adverse environments.
In addition, the flourishing period of red spiders is during the flowering and fruit setting period of strawberries, and chemical control is prone to drug damage, which also has a certain poisonous effect on bees.
Prevention and control measures for red spiders
Agricultural control
Timely removal of yellow leaves, old leaves, diseased leaves and disease residues at the bottom, in order to ensure adequate nutrient supply, you can pour 300 times the liquid of sea spirit biological stimulant to promote balanced absorption of roots and improve the stress resistance of plants.
Once a small number of plants are found to have red spiders, they are immediately treated, and it is more troublesome to look at the back of the leaves to check the insects, you can view the leaf surface, if there are small yellow dots in the shape of a clump, you will be harmed by red spiders.
Do not discard the victim pieces on the ground and then uniformly process, easy to lead to the spread of red spiders, it is recommended to put into the bucket prepared in advance, it is best to add some water, and destroy it uniformly when most of the barrel is large.
Red spiders like high temperature and low humidity environment, which is similar to the conditions required for strawberry growth, so the regulation of temperature and humidity after entering the shed is of little significance.
Biocontrol
Can be used for red spider biological control is mainly predatory mites, there are currently 4 species in China, namely Chilean small plant mite, California new small mite, courgonian blunt mite and pasteurized blunt mite, comprehensively look at the new California small mite is more appropriate.
Before releasing predatory mites, try to reduce the number of red spiders, starting after the first leaf splitting, 6,000 strawberries per acre release 5 to 6 bottles of California new small mites, release 1 leaf per plant, and replenish the release once every 30 days.
Pharmaceutical control
The best control period is before and after the mulching, and the effective agents are biphenylhydrazine ester, butyfluoro mite ester, acetazole, tetazole mite nitrile, thiomethamine, avi da emulsion, nissolon, pyridoxine and so on.
When spraying, it must penetrate the back of the leaf, the dosage and speed of application are uniform, to ensure that there is no leakage spray, no heavy spraying, pay attention to insect eggs and kill, an effective ingredient, a production season do not exceed 3 times.
When there are red spiders after flowering but no symptoms of leaf dorsal redness and silk web: (1) splitting old leaves and lying leaves, leaving 5 to 6 leaves on each side of the bud, 2 side buds above, leaving 4 pieces of each side of the bud, and splitting the point in the middle of the two rows; (2) 1500 times (or 1500 times of butylfluorocarbonate) + 1000 times of nissolon, the water consumption is not less than 4 barrels per acre, and the back of the leaf is penetrated; (3) On the second day after the drug, California Xinxiaosui releases 9 bottles per acre, and each strawberry releases 1 leaf.
When there are red spiders after flowering and the back of the leaf is red and silk web symptoms appear: (1) splitting old leaves and lying leaves, strawberries without silk mesh leave 5 to 6 leaves per side of the bud, more than 2 side buds, 4 leaves on each side of the bud, strawberries with silk mesh leave 3 leaves and 1 heart, and split the middle of the two rows; (2) 1500 times of biphenylhydrazine ester + 1000 times of nissolen, 1500 times of tetrafluorosterate at intervals of 3 to 5 days + 1000 times of nissolon, water consumption of 1 mu is not less than 6 barrels, penetrate the back of the leaf; (3) on the second day after the drug, California New Xiaosui released 13 bottles per acre, Each strawberry releases 1 leaf.
Note: The above water consumption and the release of the new small mite in California refer to the colonization of 6,000 plants per mu, and other cultivation amounts need to be adjusted appropriately.
This article is written and sorted by the agricultural assistant team, please be sure to indicate the source of the agricultural assistant (ID: nyzs360), and do not modify the content of the article, the modification must be investigated!
Agricultural assistant