Hello berry farmer friends! Spring is here! It's time for the annoying red spider to come out and do evil, an important pest that harms strawberries and is highly prevalent during the flowering period. During the nursery period, there will also be red spiders that are harmed by strawberry plants that slow down their growth, weak growth, less hanging fruit, yield loss of 25%-40%, in addition, it will also lead to small fruits, poor quality, deformed fruits, zombie fruits, and when serious, strawberry plants will not bear fruit, dwarf and die.
The most annoying thing is that the red spider is very adaptable to the environment, and the reproduction is still very fast, and it can multiply nearly a hundred times in 5-7 days. It can also spit silk cocoon, the formation of a cocoon can effectively resist pesticides and adverse environmental conditions, so it is very stubborn and difficult to fight. Because the red spider is very small and can form a cocoon, it is very difficult to observe and distinguish. Therefore, only by understanding the symptoms of strawberries being harmed by red spiders can we start prevention and control as soon as possible.
<h1 class= "pgc-h-arrow-right" > symptoms of strawberries being invaded by red spiders</h1>
Red spiders generally start from the lower leaves of strawberries and show a bottom-up trend, so during the high incidence period, be sure to carefully observe the lower strawberry leaves. If red spiders appear in the strawberry orchard, they will suck the sap on the back of the strawberry leaves and then form a cocoon. Therefore, if the initial manifestation of being attacked by a red spider is the appearance of gray spots on the leaves, this is the cocoon of the red spider. If you have unknown gray spots on your strawberry leaves, be sure to start being wary of red spiders.
Over time, the white spots will turn red and then rust red. If the entire leaf is shown to be as rusty color as if it has been burned by fire, it has basically been very badly damaged, and the diseased leaf must be removed immediately and incinerated to remove or alleviate the source of insects.
<h1 class="pgc-h-arrow-right" >how did the red spider come from? What environmental conditions are more likely to lead to the growth of red spiders? </h1>
The source of the red spider is the residual overwintering insects in the strawberry stubble field; the second is the residual female insects planted in the former stubble; the third is that the strawberry seedbed is not completely cured, and the seedlings bring the insects into the greenhouse; the fourth is the tool used in the agricultural operation with the worm, or it is simply bad luck, and the red spider elsewhere spreads to its own orchard and fruit shed with the help of wind. Red spider eggs, mites and insects that enter the orchard fruit shed through the above channels will breed immediately when the climate is suitable, causing harm.
So, what kind of environmental conditions are more likely to lead to the growth of red plants? Red spiders prefer hot, dry environments, and the higher the temperature and the lower the humidity, the faster it occurs. When the temperature is above 10 °C, the red spider mites begin to move, and the female mites begin to lay eggs at above 16 °C. This can also explain why the occurrence of strawberries and red spiders cultivated in greenhouses is particularly serious. Due to the cover of the greenhouse, which blocked the rain, and the temperature in the shed was high, the breeding rate of red spiders accelerated.
<h1 class= "pgc-h-arrow-right" > how to control strawberry red spiders?</h1>
Strawberries are in a special condition, with long flowering and fruiting periods, and the time between flowering and fruiting is very short, only 10-15 days. Therefore, if you blindly use pesticides to control red spiders, it will cause the problem of pesticide residue. In addition, some pesticides such as gram mite 2000 times liquid, although some effect, but will lead to strawberry fruit deformity, used in vain.
Therefore, in terms of red spiders, we generally focus on prevention and treatment as a supplement; physical and biological control is the mainstay, chemical control is supplemented, and the method of spray control is used when necessary.
Tend to manage orchards, weeds and maintain hygiene. Good water and fertilizer management improves the robustness of the plant, thereby improving its resistance to disease and adversity. Remove dead branches, old leaves and diseased leaves in time and burn them in a concentrated manner.
According to the characteristics of the red spider we talked about above, try to avoid the environmental conditions suitable for the survival of the red spider. For example, in water management, under the premise of keeping the soil moist, when the temperature is too high, the wind should be appropriately cooled to inhibit the rapid reproduction of red spiders.
Before strawberries bloom, pesticides can be considered for control, such as the use of 1500 times the solution of the ethyl ester suspension of spirant or, 43% of the hydrazide suspension 2000 times liquid, spraying the stems and leaves.
After flowering, in order to ensure the safety of strawberries, you can consider releasing the natural enemy of the red spider: planting mites for control. Plant mites can cut through the cocoons woven by red spiders, eat red spiders, and especially like to eat red spider eggs. However, plant mites are very sensitive to pesticides, if the use of plant mites for control, we must reduce the use of pesticides, so as not to be injured by mistake. At present, the varieties of plant mites suitable for the control of red spiders have been screened out, such as the two blunt mites, the long-haired blunt mites, and the Okinawa blunt mites. In addition, aphid-eating flies and seven-star ladybirds are also natural enemies of red spiders.
If the harm situation of red spiders is already serious and requires the use of pesticides, it is best to choose biological pesticides such as pyrethroids and matrine. A 1:1 mixing of the two agents to spray the front and back of strawberry leaves also has a good effect.
Eliminate the strawberry red spider must grasp the time, according to the particularity of strawberry crops, for the use of drugs, in order to effectively reduce the harm, I am a farmer Lao Wang, pay attention to me, every day to learn a little bit of agricultural technology knowledge!