1. Fruit rust caused by spraying 1. 1 Choose pesticides with high concentration and excessive dosage. Most fruit farmers are worried that peaches will be harmed by pests and diseases after bagging. After flowering, gradually spray pesticides, apply pesticides in excess concentration, and mix a variety of pesticides, fungicides and pesticides. During the discoloration period, the fruit surface is stimulated by drugs, and various irregular spots are prone to appear on the fruit surface, resulting in poor smoothness.
Control measures: When the flowers wither by 70%, spray 1 times mixed protective pesticides, fungicides and insecticides to prevent the infection of germs, and prevent budding insects and green blind stinkbug. Spraying 1 times of therapeutic pesticides, fungicides and insecticides before bagging to kill germs and larvae on the fruit surface. After bagging, spray medicine at normal time to prevent disease immediately.
1.2 When spraying highly irritating pesticides, blindly follow the trend, except for high-concentration pesticides, pesticides containing heavy metals such as manganese and zinc, acetamiprid Chinese medicine preparations, copper preparations, etc. Prevention and control measures: Spraying before bagging, choosing water dispersible granule, liquid, emulsion in water, microemulsion, suspending agent and wettable powder, and avoiding using copper preparation and acetamiprid traditional Chinese medicine preparation.
Mancozeb is a good protective pesticide fungicide, which can be divided into two types: fully complex state and partially complex state. Mancozeb in fully complex state is safer after use, and some complex States are prone to iodine ion erosion. Therefore, it is not advisable to spray mancozeb in a partially complexed state before bagging. It is best to choose clonidine wettable powder or water dispersible granule, azoxystrobin or pyraclostrobin. And the adverse effects of application are smooth and meticulous.
1.3 when the application is uneven, the wettable powder and water dispersible granules are directly poured into the whole water flow to mix, which can not fully dilute the drug; In the process of spraying medicine, there is no need for reflux pipe and frequent stirring, resulting in the deposition of liquid medicine and inconsistent concentration values. Preventive measures: Wettable powder, soluble granule, microemulsion or water dispersible granule must be diluted twice before use. When spraying, if there is no return pipe, a specific person can keep stirring, so that the liquid medicine does not precipitate and is evenly distributed when spraying.
Second, the fruit bag contains 2. 1 moisture, and some fruit farmers bag it after spraying, and the leaves and fruit surface are not dry. In a short time, the liquid medicine in the paper bag is not completely dried, and the environmental temperature in the bag is high, which is easy to burn the fruit surface and produce rust spots. Preventive measures: spray medicine in the morning, bag it in the afternoon, or bag it the next day after spraying medicine, so that the liquid medicine on the fruit surface is fully dried and completely digested and absorbed by epidermal cells on the fruit surface.
2.2 Bagging in wet and foggy days Some fruit farmers bag at full speed after dawn. The surface of the fruit is mostly dew. After bagging, the dew is in the paper bag, and the temperature in the bag is high, which turns into steam, resulting in long-term water vapor winding in the paper bag and scale. In strong convective weather, the indoor space in the park is humid, so it is easy to put water into paper bags when bagging, which is easy to cause scale on the fruit surface. Prevention and control measures: It is safest to bag in sunny or cloudy days. Dewdrops on the surface and leaves of fruits can't dry in the morning, so don't bag them. Be sure to wrap the leaves and leaves when they are dry with dew.
Third, the technical problems of bagging 3. 1 Paper bags are of poor quality and are not resistant to rain. In addition, the frost red variety matures late, and it takes more than four months from bagging to picking, and it has to go through all the main flood seasons and many days of wind and rain. The quality of the paper bag is poor, water easily enters the fruit bag, and fruit rust occurs on the surface of the fruit. Prevention and control measures: choose high-quality virgin pulp paper, two-layer paper bag, with wax in the outer paper, which is resistant to sun and rain.
3.2 Late bagging time. Most fruit farmers mistakenly think that the bagging time needs to be delayed when the frost red peach matures late, and some delay time is until July. Because of the late bagging time, the weather has been stormy, and there are many opportunities for pests and diseases, and the fruit surface is prone to mild insect spots or diseased spots. Prevention and control measures: the best bagging time is from the middle and late May to the end of June, and the end of June at the latest.
3.3 Bagging technical problems: When the fine wire is tied, the peach leaves are tied together, and when it rains, precipitation enters the paper bag through the peach leaves; Some winds easily open their mouths, and precipitation enters the bag, leading to fruit rust. Prevention and control measures: ensure three tightness when bagging, and the mouth of paper bag should be around the branches; What matters is expansion and contraction; When binding, tie the wire firmly to prevent precipitation from entering the bag.
3.4 After bagging, the paper bag rubs the fruit surface. Because the paper bag is not unfolded when bagging, when the wind blows, the paper bag shakes back and forth and rubs the fruit surface, which is easy to produce rust spots. Precautions: Before bagging, unfold the paper bag with your fist and then cover it.
Fourth, fruit farmers who have long bagging days after partial spraying save trouble, spraying 1? 10 after each dose? Many days. ? Because of the long bagging time, bacteria are easy to infect and pests are easy to harm, resulting in disease spots. ? Control measures: the best bagging days after spraying are 7 ~ 8? D, because the residue period of pesticides is about 7 ~ 10? d .