Deep plowing, fine plowing and irrigation in winter are not only important measures for increasing cotton production, but also effective methods for eliminating overwintering cotton bollworms, and they can get twice the result with half the effort.
1, deep plowing in winter. The bollworm is generally wintering 2.5 to 6 centimeters from the ground (up to 9 centimeters in depth). Winter plowing can destroy the diverticula, change the natural state of the carcass and reduce the emergence rate of late springs; some insects can be turned to The ground surface causes it to dry, freeze to death or be eaten by natural enemies; some insects can be turned into the deep layers of the soil, so that they can not be properly feathered and drowned to reduce the source of overwintering insects. The sooner the winter plowing time is, the better. Generally, after the harvest of the former crop, it must be carried out. Before the earth is frozen (more than 5 cm in the frozen soil layer), it will be cultivated to prolong the weathering time, improve the pest control effect, and facilitate the multi-admission. Rain and snow. The depth of ploughing should be more than 10 cm; the deeper the winter ploughing, the better the worming effect. It should be noted that due to the strong fly ability of the adult Helicoverpa armigera, winter plowing must be carried out in large areas in order to be effective; in addition to the reserved white cotton land, wheat fields are interplanted, orchard gaps, and winter plowing is also required.
2, cultivating and combining. Before the winter ploughing, the hoe should be smashed again. After the ploughing, the smashing and smashing can be performed. The water can be stored and the squat can be killed. According to surveys, the first winter plowing in cotton fields can kill 76% to 85.6% of the cotton bollworm pupae. After plowing winter plowing, pupae are buried deep in the soil, which can reduce the survival rate by 86.4% to 92.5%; according to Shandong Academy of Agricultural Sciences Observed, after the winter ploughing followed by the depression, the spring water content of 5 cm soil layer was 16.4%, while only 8.2% was not.
3, irrigation after cultivation. After winter ploughing followed by winter irrigation or spring irrigation, not only can the soil be settled and weathered, but also the mortality rate of overwintering lice can be increased. According to a study by the Chinese Academy of Agricultural Sciences, when the relative soil moisture content is 40%, the mortality rate of Helicoverpa armigera is 35.7% and the emergence rate of adult is 40%. When the soil moisture content is 70%, the mortality rate of Helicoverpa armigera is 46.7%. The eclosion rate was 33.3%; when the soil moisture content was saturated, the mortality rate of pupa was 100%. According to other data, the wintering mortality rate of cotton bollworms is about 80% for winter plowing and winter plowing, and the wintering mortality rate is 60% to 70% for plots that have not been cultivated, and only 30% for non-irrigated plots. ~40%.
Virus Specimen Collection Tube
Features
1. Medical grade polypropylene material, high transparency, high sealing and low temperature resistance;
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Applications
Used for the collection and transportation of clinical influenza, avian influenza, hand-foot-mouth disease, measles and other virus specimens, as well as mycoplasma, ureaplasma, chlamydia and other specimens.
Mixed sample tubes hold more swab heads, so the retention fluid capacity is often larger. For example, single swab retention solution is generally 3ml, 10 and 1 sample tube retention solution is generally 6ml, 20 and 1 retention solution is 10-12ml. The same amount of viral nucleic acid (e.g. 300copies) is stored in 3ml, 6ml, and 12ml copies in concentrations of 100copies/ml, 50copies/ml, and 25copies/ml respectively. Obviously, the greater the number of mixed tests, the lower the virus concentration, the higher the detection sensitivity will be required.
The more the number of mixed tests is, the contact surface between the swab head, the preservation solution and the tube wall will be doubled, which will lead to the increased probability of viral nucleic acid adsorption on other swab heads or tube wall. These factors all lead to higher requirements for system sensitivity.
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