Corn top rot has become a new type of disease in summer maize. It has been on the rise in recent years and the damage is more serious. At present, farmers' symptoms and prevention measures for corn top rot are not very clear. Xiaobian is introduced in detail here for farmers' early reference.
1 symptom performance
Field observations revealed that the heart leaves protruding from the bell mouth were chlorotic and yellowish, and some of the leaf margins became thin and white. As the disease progressed, brown rot appeared on the top of the leaf, and the decayed part expanded downward along the edge of the tip. The leaves on the top of the plant with early onset and heavy onset are tightly wrapped and adhered together, showing a "shooting tip" shape, which is prone to rot and the tassel cannot protrude. According to relevant information, the symptoms of corn top rot are complex and diverse, and other symptoms are as follows:
(1) There is a knife-cut nick at the base or edge of the leaf-edge sensible leaf. The leaf margin and the top chlorotic are yellow-colored. In severe cases, one half of the leaf or the whole leaf falls off, leaving only the midrib and the midrib. A small amount of mesophyll tissue remaining.
(2) The leaves at the base of the leaves of the dead leaves are brown and rotted, and the leaves sometimes tear, or broken leaves. In severe cases, the tips of the top 4 to 5 leaves or the whole leaves die.
(3) The twisted wrap-shaped top blade is curled into an upright long whip, and some are wrapped by other leaves when forming a whip, and cannot be stretched to form a bow. Some of the top leaves are twisted and entangled and cannot be stretched, and the tangled leaves are Often tearing or wrinkling.
(4) The diseased plants with brown rot of the leaf base of the leaf sheath and stem rot-type ear stalk often rot in the leaf sheath and stem medulla, and the stalk cortex on the inner side of the sheath and the close stalk rust is rotted. In the stem, it can be seen that the internal vascular bundle and the stem section have brown spots or short strips of discoloration, and some have voids, endogenous white or pink mildew, which is easy to fold when windy.
(5) The elliptic-type ear lobe leaves and stems are yellowed, the leaf sheath stalk tissue softens, and the top of the plant is inclined to one side.
(6) Some of the top leaf clusters are susceptible to apical apex and erect.
(7) Affected or empty stalk-type plants with light disease can be sharpened, but the ears are small and the seeds are less; the severe females and tassels are aborted, deformed and unable to head, or form empty stalks.
2 Causes of the disease
Corn top rot can be divided into fungi type and bacterial type, and it is easy to occur in the trumpet stage when it encounters high temperature. Especially in high temperature, rainy, strong light climate conditions, it is easy to damage the young tissue at the top of the blade, resulting in rapid invasion of bacteria. In addition, the daily spit water and high temperature climate of the corn are beneficial to the large number of bacteria, causing a large amount of rot at the top of the blade. . In general, the incidence of corn rot in low-lying plots and soil-heavy plots is heavy.
(1) Fusarium rot disease showed symptoms in the period from maize seedling to adult stage, and the heart leaves rotted from the base of the leaves, tightly wrapped around the inner heart, making it unable to expand and whip-like; or the base of the heart leaf Cracking, blade deformity, shrinkage or distortion. The plants are often dwarfed, and the base of the stem can be seen to be longitudinally cracked and have brown lesions; the severely ill plants are not strong or the ears are small and even dying. Pathogenic bacteria generally invade from young tissues such as wounds or stem nodes and heart leaves, and the damage of insect pests, especially thrips and aphids, can aggravate the occurrence of diseases.
(2) Bacterial rot can occur before the corn is squirmed. The typical symptoms are that the heart leaves are gray-green, water-deficient, withered, forming a dead seedling or a cluster of seedlings; the base of the leaves is water-soaked and rotted, the lesions are irregular, brown or yellow-brown, and the rot has or has no special odor and mucus; In severe cases, the whole heart can be pulled out by hand, and the heart of the light disease plant can not be distorted. High temperature and high humidity are conducive to disease prevalence, and wounds caused by pests or other causes facilitate the invasion of germs. Mostly after the rain or after irrigation in the field, the plots with low or poor drainage are heavier.
3 Prevention methods
(1) Make full use of sunny weather to speed up the process of shovel, remove moisture and heat, eliminate weeds, improve seedling quality and enhance disease resistance.
(2) Timely fattening the corn fertility process into the big bell mouth period, it is necessary to quickly apply nitrogen fertilizer to the corn, especially for the heavier plots. At the same time, it is necessary to spray the micro-fertilizer on the foliar surface, and spray the functional fertilizer of Prideon fish protein in the United States to promote early seedling growth, supplement nutrients and improve the resistance to stress.
(3) Pharmacy prevention and treatment to achieve early detection and early medication. In the early stage of the disease, 58% metalaxyl · manganese zinc wettable powder 600 times solution, or 70% methyl thiophanate 700 times solution, or 50% carbendazim WP 500 times solution, plus 72% agricultural streptomycin 2,500 times of water solvent, mixed spray control. The key to the application should be directed at the heart of the diseased plant. The diseased plant should increase the amount of liquid, and control it 1 or 2 times according to the incidence. For the leaves that are stuck together, the blade should be grasped with a knife tip or an awl to pick up the adhered leaves to promote the growth of the apex and the normal development of the tassel. Under the conditions of ventilation and sun exposure, the diseased tissues will quickly dry up and effectively control the development of the disease. When the disease is late, the plants have been headed, and it is difficult to spray in the field. At this time, the control measures for spraying are not recommended.
More pesticide knowledge , please pay attention to China Pesticide Network
NY240 Engine 1 Series:power Range 900KWm-2640KWm
Engine.900KWm-2640KWm
CCSN POWER GENERATION INC.(Engine is a subsidiary of CCSN) , https://www.ccsnengine.com