First of all, disease, is the meaning of menacing, refers to the acute epidemic of infectious diseases.
Take "epidemic" of plant diseases, acute disease is easy to spread rapidly, often epidemic disease, once caught, will cause great damage to crops.
In the potato is the staple food of Ireland in the 1840 s because of potato late blight pandemic killed 1 million people in hunger, Inner Mongolia in 2007 bayinnaoer because tomato late blight popular 638900 tons of production loss, accounts for nearly 30% of total output.Almost every year since the early blight, cotton blight, the popularity of disease and other diseases, result in all parts of the country potatoes, tomatoes, peppers, eggplant and other crops or light or heavy losses.
The cause of the disease in these seemingly related to weather, also is the "year" and the farmer said, actually also and most people lack of understanding of the disease epidemic rules, for negligence or improper measures related.
Early, late blight of disease and epidemics and cotton blight disease occurred in four time, host plant species and has a certain difference on the occurrence conditions, what is more important pathogen in parasitic ability and the different pathogenic ability, on the disease spot extension process is different also, due to the difference of symptoms.
1, name of disease because of different host plants and: though are the result of the flagellar bacterium infection, but tomato and potato late blight (mold) caused by disease, eggplant and moulds) (note to disease and pepper (capsicum sojae) disease;
2, different time: early blight of English name call early blight, late blight is newest blight.In general, early blight occurred in the earliest potato or the flowering of tomato fruit stage, late blight in young fruit to the front of the fruit harvest, cotton blight happen suddenly clears after the rain, close to the surface of the lower part of the fruit;
Differences in 3, the conditions: early blight of appropriate temperature in 24 ~ 29 ℃, relative humidity in 31 ~ 96%, and that is warm and humid weather beneficial bacteria breeding, and infection, but the potatoes and tomatoes such as the host, strong resistance to germs before flowering, in full bloom fell rapidly, especially the lower leaflets, therefore, early blight of initial period in blossom period;Formed late blight of sporangia germination zoospores of optimum moisture is saturated, there is water, the optimum temperature is 12 ~ 15 ℃, 15 ℃ higher than the sporangium germ tube invade the host directly, but need a longer time;Invade into host body of hyphae spreading fastest when 20 to 23 ℃, and fastest symptoms.Under production, 24 ℃ during the day (extension) in infected tissue, below 10 ℃ at night (into), relative humidity is more than 85%, especially in the water film or water droplets, that is, when the weather sounds, broke out easily.Late blight of parasitic ability a little less than early disease, often happen after the potato late flowering;
4, parasitic, and the difference on the pathogenic cause different symptoms: early blight pathogen belongs to the imperfect ascomycetes ascomycetes the chain inside or spore;Late blight, epidemics, and cotton blight pathogen belong to them, inside of the fungus;Chain, spore fungus parasitic ability compared with several other bacteria is a bit a few stronger, the less risk.Germs invade into the blade side released after a half quinone derivatives material poison cells and tissues, extension, but because of the ups and downs or weather day and night temperature change, the rate of infection is fast or slow, alternation in host body extension, so the formation of the disease spot with the grain, and the disease spot around the leaf tissue often first large area of green yellow;Late blight pathogen parasitic ability is worse, to invade the host, and obtain the nutrition we must produce more of the toxin to kill a large number of host cells, so, late blight disease spot formed faster, disease spot is like the same dark green been scalding water, infected tissue almost no resistance reaction was killed;
5, because the bacteria different form the telltale signs of a significant difference between the two categories: in fact, the process of germs infect plants is also bacteria breeding process itself.Pathogen to the prevention and control of disease is not good, it is because of evolutionary status, the more lower biological breeding way more simple, reproduction rate is higher, the reproductive body: spore, the more popular fungicide is often difficult to fully control.
Sickness, is the pathogen in infected breeding body parts.
Early blight pathogen belongs to the higher fungi, when disease occurs after a period of time, pathogenic bacteria in the disease spot is formed on the surface of the large number of film of conidium.Late blight and blight pathogen belongs to the lower fungi, such as clone formation sporangium and germination of zoospores, as long as the appropriate temperature especially humidity, produce spores will be very fast, so late blight, epidemics, and cotton blight appeared shortly after the disease spot will be on the back of their disease leaves or ill health organization border or disease spot surface appear white hair mould.
