![]() Once begun, late blight tomato disease can sweep through acres in a matter of weeks. Each late tomato blight lesion can produce up to 300,000 sporangia a day and each of those sporangium are capable of forming a new lesion. The late blight symptoms become more obvious when the area around the lesions appears water soaked or bruised and turns grey-green or yellowed. The tiny lesions of late tomato blight are hard to spot and sometimes go unnoticed. If the weather is damp and the temperature moderate - just like most rainy summer days - the pathogen would sporulate around these lesions and the late blight tomato disease will be ready to spread to the rest of the garden and beyond. Small lesions appear on stems, leaves, or fruit. Once infected, late blight symptoms will become visible in three or four days. Tomato late blight needs only a few hours to take hold. All it wants is a little free moisture on the leaves from rain, fog, or morning dew. Sporangia from an infected plant are carried through the air, sometimes several miles, and once they land on a suitable host, germination is almost immediate. Phytophthora infestans, the pathogen that causes tomato late blight, needs tissue to survive. Vigilant observation and pre-treatment are the only defenses against late tomato blight. On tomatoes, the fungus-like organism can destroy a crop within days if conditions are right. It was the leading factor in the Irish Potato Famine of the 1850’s, when millions of people starved because of the devastation wrought by this deadly disease. This means that there are many things we can do to prevent the introduction of this devastating disease into new fields.Late blight tomato disease is the rarest of the blights that affect both tomatoes and potatoes, but it is also the most destructive. Human transport of infected plant material is the most likely cause of the long-distance movement of Phytophthora blight in New York. They are also moved long distances in infected plant material, especially cucurbit fruits which may appear healthy at harvest, but rot within several days. Long-lived spores in the soil can be moved throughout or between fields when soil clings to tires and tillage equipment. Culled fruit may contain oospores Long-lived circular oospores, magnified 200 times Swimming spores are attracted to plant roots as they move through water. Essentially, these spores will move wherever water moves, including draining into surface irrigation sources like streams or ponds, from which they can be spread throughout entire fields, or from one farm to another within a watershed. They can also be splashed to aerial parts of plants or between plants by heavy or wind-blown rain. Short-lived spores can be moved long distances (more than 200 feet) through standing water in a field caused by heavy rain, poor drainage, or over-irrigation. capsici cannot be blown between or within fields. Symptoms of Phytophthora blight on a pumpkin Symptoms of Phytophthora blight on an eggplant Symptoms of Phytophthora blight on a pepper leaf How the pathogen spreads It is sometimes accompanied by a shriveling of the crown, and fruits may develop soft spots, then “melt.” When humidity is high, fruits, stems, crowns, or leaves may become covered with spores. Phytophthora blight often appears first in low or flooded parts of a field as systemic wilting of the plant. Unfortunately, this is common in New York fields. capsici (called A1 and A2) come in contact with each other. They can only be produced when two different types of P. Neither of these spores can survive the winter in New York, but both are very important in the spread of Phytophthora blight during a growing season. The “powdered sugar” on infected plants is actually made up of millions of lemon-shaped spores that release smaller swimming spores in water. Phytophthora blight is caused by the water mold Phytophthora capsici. It is important to know how to prevent the disease from infecting your vegetables, as well as how to manage the disease after infection. Fruit rot is more common on pumpkins, winter squash, cucumbers, and melon, while root and crown rots are more common on peppers and summer squash. The host range includes cucurbits such as melon, cucumber, pumpkin, and squash, the Solanaceae including peppers, tomato, and eggplant, legumes such as snap bean and lima beans, and weeds such as wild night shades, purslane, and Carolina geranium. Phytophthora blight causes fruit rot, rapid wilting, and plant death in many vegetables. Phytophthora blight on peppers (LIHREC website).Phytophthora blight on eggplants (LIHREC website).Phytophthora blight in cucurbits (LIHREC website).Phytophthora blight on beans (LIHREC website). ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |