Recently, the weather has changed a lot, the drought and flood have turned sharply, and the soil environment of rice rhizosphere has changed greatly. It has different effects on rice growth, which is easy to cause rice production disorder and the ability to tolerate herbicides . In addition, many pesticides are aggravated because of the application of heat in sunny weather.
From late July to early August, rice from all regions will enter the jointing stage, and the application of herbicides in rice fields is more risky, so be careful.
1 Pharmacy compounding appears antagonistic
Although cyhalofoprin can be rapidly degraded in rice to a diacid state inactive to acetyl-CoA carboxylase, it is highly safe for rice. However, cyhalofoprin has antagonistic effects with 2,4-butyl butyl ester, 2 methyl 4-chloro, bentazone, and sulfonylurea. When mixed, the efficacy of cyhalofoprin is reduced, and the phytotoxicity is also increased. risk.
2 Part of the planting of Jinyan 818 and other varieties of the field appeared phytotoxicity
This year, some of the fields of Jinjing 818 and other varieties were planted, reflecting the occurrence of phytotoxicity, and some of the rice leaves have obvious contact plaques.
If the imidazolinone herbicide is applied in the near future, please note that the dosage should not be too large (when the machine is inserted into the field without the crabgrass, it can effectively prevent the weedy rice by slightly lower than the recommended amount, and the safety will be improved accordingly) The concentration of the drug should not be too high. Do not re-spray or leak spray. Establish a layer of water in the field one or two days after application, and open the water shortage to ensure that the field is not dry or flooded.
In addition, take care to avoid applying the medicine in the windy weather, avoiding the liquid medicine floating to the ordinary paddy fields and avoiding the flow of the field water into the ordinary paddy fields.
3 Continue to be sunny and hot, pay attention to medication risk
At present and in the future, it is the peak period of rice field stem and leaf treatment to supplement residual weeds. (For example, after planting rice and direct seeding rice in Jiangsu Province in mid-to-late June, the stems and leaves are weeded at the end of June and July, and the residual weeds are usually replenished in the middle and late July.)
In the high temperature period, the application of bentazone, flufenoxyacetic acid, 2 methyl 4-chloro, oxazolamide, benzoxazole and other drugs is prone to phytotoxicity, pay attention to prevention and control risks.
(1) Symptoms of contact with phytotoxicity
On the sunny day, the application of bentazone, flufenoxyacetic acid and other drugs may appear to be similar to the local blight of rice leaves. For example, a farmer in Taizhou applied flufenoxyacetic acid at the end of mid-July to control the weeds, causing more serious contact damage to rice.
If only the herbicide is killed, there is no need for ambulance. If the rice seedlings are harmed by bentazone and flufenoxyacetic acid, they can be protected by water and a shallow layer is recommended in the field.
Both of the above drugs will kill the rice leaves, causing the leaf tissue to collapse, losing water and drying up, and losing a lot of water in the leaves may cause the seedlings to lose water and physiologically lack water. In severe cases, the whole plant will die. Irrigation can alleviate the physiological water shortage of rice seedlings and has a certain protective effect.
In summary, we must pay great attention to the safe use of drugs, and try to avoid applying the drugs on sunny days.
(2) hormonal herbicides
1 2 methyl 4-chloro, hormonal herbicides, rice seedlings are highly susceptible to phytotoxicity. Symptoms of phytotoxicity are dwarfing of plants, malformation, yellowing of old leaves, fading of stems, failure to extract properly, curling, forming a ring at the base of the stem, swelling of the base of the stem, mildew, and giving birth to short and thick secondary roots. In severe cases, the base of the stem is rotted and the whole plant is dead.
Note: The use of 2 A 4 chlorine should be used from the 3rd leaf stage to the jointing stage. After the rice jointing, it is easy to produce phytotoxicity, which leads to the chlorosis and yellowing of the seedling leaves, the new leaf onion tube, the ear curl is difficult to extract, and the ear deformity And other symptoms.
2 quinclorac and quinclorac are special selective herbicides for controlling rice sorghum, belonging to hormone-type quinoline carboxylic acid herbicides. The symptoms of weed poisoning are similar to those of auxin, mainly used for controlling cockroaches. Grass has a long pot life and is effective in 1 to 7 leaf stages.
The phytotoxicity mainly occurred in Putian and live fields. After half a month of application, the symptoms were obvious, and it was also possible to suffer damage to the fields. After transplanting to the field, the symptoms were manifested.
The typical symptom is that the sheath of the seedling is completely healed into a tubular shape with green leaves, and the leaves are dark green, and the distortion is severe and obvious. After the phytotoxicity, the rice heart onion tube curls and cannot be unfolded. This is actually an excessive use of quinclorac.
How to determine the herbicide phytotoxicity?
Before and after the 3 leaf stage of rice, it is the season of stem and leaf treatment and weeding. At this time, improper application of the rice leaves may cause yellowing of new leaves of rice seedlings. If the field did not use these herbicides at the time, this factor could be ruled out.
In addition, herbicide phytotoxicity often has its specific distribution pattern in the field. Generally, it will follow the application route, and there will be symptoms of phytotoxicity ranging from mild to heavy, because the fight is always impossible, and the symptoms will be heavy. One point, where the application is less, the symptoms will be lighter, and often along the route of the fight, the strips are distributed in a strip shape.
If the situation is observed in the field, the damaged rice seedlings are evenly distributed in the field, and the degree of damage is roughly the same, and the possibility of phytotoxicity is small.
What should I do if a phytotoxicity occurs
The recent weather is sunny and hot, and the temperature is high. Excessive dehydration in the field will aggravate the adverse effects of high temperature and physiological water shortage. In the daytime, the field should be filled with water and nursery. (When rice is poorly grown due to high temperature, physiological water shortage, etc., it is easy to aggravate the phytotoxicity when applying oxazocilin.)
Gibberellic acid, indole acetic acid, indolebutyric acid, etc. are usually targeted drugs that alleviate phytotoxicity. For example, fenoxapropion mainly inhibits the growth of new tissue, and it is better to use gibberellic acid after phytotoxicity. If there is phytotoxicity in the paddy field, it is recommended to spray the brassinolide or the phlegm, which is conducive to the recovery, 5 to 7 days, depending on the recovery.
From late July to early August, rice will enter the jointing stage, and the risk of applying herbicides is greater.
In the case that the season is very tight and the medication window is short, in order not to miss the application period, the relationship between weeding and phytotoxicity can be weighed according to local conditions, and early application is possible. In the sunny days, as long as the rice grows normally, it can still be applied in the evening after the temperature drops in the afternoon.
(Source: Daily Agricultural Materials, Shuiqing Farm)
4 Inch Floor Trap,4 Inches Floor Drain,Stainless Steel 4 Inch Floor Trap,4 Inches Square Shower Drain
Kaiping City Jinqiang Hardware Products Co.,Ltd , https://www.jmkimpowerdrain.com