Pear rust disease pictures and control methods
Pear tree leaves grow similar to "goat's beard" like fluffy things, yellowish-brown, a piece of black. "like fluffy things, showing a yellowish-brown color, a piece, over time the leaves will turn black, eventually lead to pear tree leaves dry and fall off.
Pear tree leaves grow this "sheep's beard", in fact, is a disease of the pear tree, belonging to the fungus spreading disease pear rust, but also called red star disease, there are farmers figuratively called it "sheep's beard disease". .
Pear rust occurs in pear trees because it is usually associated with nearby cypress trees. Pear rust occurs when there is a rust fungus that passes through the host and then spreads to the pear tree, causing the rust to occur.
But cypress trees are mainly the hosts of rust spores, so most of the causes of pear rust on pear trees are related to the presence of cypress trees planted nearby. In the management of the orchard, if you can not change the planting environment of the pear tree, then you need to carry out timely integrated control.
Symptoms of pear rust
Pear rust first occurs in the pear tree leaves, pear tree leaves are infected with rust fungus, eroded by the fungus, leaf surfaces will appear reddish or yellowish-brown patches.
In the absence of timely prevention and treatment, the spots will gradually spread, deepen in color, spread most of the leaves, the spot site is abrupt, between which there is a black fungal spot.
Pear rust disease in the late stage, in the onset of pear tree leaves behind, will emerge about 4 cm long, fluffy yellow-brown things, like "goat's beard".
In fact, this is the pear rust spores, spores ripe rupture, visible inside the yellow-brown powder. Pear rust disease can lead to the loss of pear tree leaves photosynthesis function , later pear tree fruit is infected can cause fruit rot.
The cause of pear rust
The spring spores of pear rust can cause neighboring cypress trees to become infected, and when the cypress trees become infected, a brown substance will appear on their shoots or leaves, and gradually grow to a length of about five centimeters.
The brown material breaks down under the action of natural external forces such as wind or rain, and becomes sticky reddish-brown material when it gets wet, which is a spore mound formed by several small spores. These small spores spread with the help of the natural environment, which leads to the disease of pear trees around cypress trees.
Pear rust integrated control measures
Through the content of the above understanding of the characteristics of the disease, and the transmission of pear rust, the best measures to control pear rust, is to change the environment around the pear garden, in the spore can be spread within the scope of the removal of cypress forests, the spore propagation distance usually reaches about 5 miles.
But removing the surrounding environment is not usually possible, then a combination of drugs is needed for control.
Growers can apply tebuconazole to cypress plants within the effective transmission pathway around the pear orchard in the pre-spore spread period, approximately after March each year and before August each year. for boarding spore inactivation, so as to achieve the prevention and control of spore transmission, reduce the induction of pear rust.
Secondly, in the rainy season every year, when there is effective rainfall, about a week's time, timely to the pear orchard around the cypress and other trees of the same family, the spraying of diclofenac zinc, phenylmethylpropiconazole, phenyl ether metronidazole and other drugs of any of the kind .
At the same time, pear trees should also be sprayed to do double control, pear trees can be sprayed with allyl alcohol one to two times, the application of drugs to the leaves of the front and back evenly sprayed to achieve complete control.
Summary of the pear tree leaves, once found to have grown similar to the "sheep's beard" hair, do not take it lightly, may be pear rust, should be fully attention.
Pear rust, if you do not get timely and effective prevention and treatment, pear rust will also be transmitted to the fruit, not only will affect the function of the pear tree leaves, even the fruit is difficult to protect.