Pea nut crop diseases A Lecture by Mr Allah Dad Khan

Pea nut crop diseases A Lecture by Mr Allah Dad Khan

• 6.
  SYMPTOMS  Leaves onmain stem turning chlorotic and wilting; entire plant wilts very rapidly when there is a period of water stress following high moisture; clusters of red-brown fungal bodies occur on on stems, pegs and pods; roots destroyed; roots blackened and shriveled
• 7.
  CLUSTERS OF FUNGALFRUITING BODIES ON PEANUT STEM PLANTSYELLOWING AND WILTING
• 15.
  PEANUT PLANT INFECTEDWITH CERCOSPORAFUNGUS PEANUT PLANT INFECTEDWITH CERCOSPORA FUNGUS
• 16.
  SYMPTOMS  Characteristic orange pustuleson undersides of leaves which become covered in masses of red- brown spores; pustules may form on pods
• 17.
  SYMPTOMS  Lateral branchesor main stem yellowing and wilting; white fungal mat developing on the stem close to the soil line; white to brown spore containing structures developing from the fungal mats  Cause  Fungus  Comments  Pathogen has a large host range and attacks many crops including sugar beets; disease favors dry soils which crack deeply, allowing the penetration of oxygen  Management  Plow crop debris deeply into soil after harvest of crop; crop rotation of 3-4 years are very effective at reducing soil inoculum in the case of severe infestations; applications of appropriate fungicides can help suppress stem rot but care should be taken with selection as some pesticides (e.g. benomyl) are known to increase the severity of the the disease
• 18.
  SYMPTOMS  Chlorosis ofleaf margins; curling leaves; loss of leaf turgor; plants wilt and become stunted as the disease progresses; plants wilt rapidly during periods of water stress; vascular system becomes dicolored  Cause  Fungi  Comments  Fungus can survive in the soil for several years; disease is spread to uninfested fields by movement of infested soil or contaminated tools and machinery; there are no peanut varieties known to have resistance to the disease  Management  Irrigate plants frequently to reduce wilting of infected plants and allow them to reach maturity; eliminate weeds int he plantation which may allow inoculum to build up in the soil; remove and destroy infected crop residue after harvest to reduce inoculum in the field 
• 19.
  SYMPTOMS  Seed and un-emergedseedlings attacked by the pathogen are rapidly shriveled and dried. Brown or black mass covered by yellow or greenish spores may be seen. Decay is most rapid when infected seeds are planted. After seedling emergence cotyledons already infected with the pathogen, show necrotic lesions with reddish brown margins.This necrosis terminates at or near the cotyledonary axis. Under field conditions the diseased plants are stunted, and are often chlorotic.The leaflets are reduced in size with pointed tips, widely varied in shape and sometimes with veinal clearing
• 20.
  SYMPTOMS  This diseasecan result in poor stands after planting and/or death of entire plants soon after emergence of seedlings.As plants develop woody stems and tap roots, this disease is less likely to occur.The succulent and elongating hypocotyl of seedlings is highly susceptible to this disease. Diseased tissues will appear sunken and tan to dark brown in color. Masses of black sooty spores of the fungus usually cover the decayed tissues.
• 21.
  SYMPTOMS  Circular, brown-blacklesions on the upper surfaces of the leave; web or net-like brown lesions on leaves may form on leaves during periods of high humidity; as sisease progresses, lesions darken and develop a rough texture; lesions may cover entire leaf surface
• 22.
  SYMPTOMS  Numerous spotson upper surface of leaflets; entire plant or discrete parts may wilt and die; pods and stems become covered in fungal sclerotia  Cause  Fungus  Comments  Disease emergence favors high moisture and high temperature; plants damaged by frost or other pathogens are particularly vulnerable to attack  Management  Avoiding frost damage by planting early peanut varieties can help protect the plant from fungal colonization; application of appropriate foliar fungicides (e.g. benomyl), where available, can help to control the disease