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Bud Necrosis/Stem Necrosis

General              caused by PBNV transmitted by thrips (Thrips palmi)   Symptoms first appear on young leaflets as faint chlorotic spots (Right leaflet in the Fig.) that may develop into chlorotic or necrotic rings and streaks (Left leaflet in the Fig.1)

Fig. 1

Fig. 2

Symptoms Later the chlorotic spots and necrotic rings and streaks spread on all the leaflets of plants (Fig.2) and the plants die.

Bud Necrosis Symptoms Terminal buds of plants are affected when temperatures are relatively high(Fig.3)

Fig. 3

Fig. 4

Symptoms Leaflets produced on auxiliary shoots show a wide range of symptoms including reduced size, distortion of the lamina, mosaic, and general chlorosis (Fig.4).

Symptoms

Early infection results in stunting of plants due to multiplication of affected terminal buds (Left Fig.).
Any seeds produced by early-infected plants are small, shriveled, and with spots (Right Fig.).
  

Management

Use resistant/tolerant cultivars: ICGS 11, ICGS 44, ICGV 87141, ICGV 87187, ICGV 87119, ICGV 87121, ICGV 87160, ICGV 87157, or ICGV 86590. Control thrips as the disease is spread by these insects.   Early sowing (15 June to 15 July) may avoid the peak disease incidence. Establish and maintain high plant density of groundnut crop. Intercropping of groundnut with cereals like pearl millet will restrict spread of the virus. Avoid groundnut cultivation adjacent to the crops that are susceptible to bud necrosis, such as green gram or black gram.

Stem necrosis  (Peanut Sterm Necrosis Disease)

General:

• PSND caused by  Tobacco Streak Virus (TSV)
  
• Transmission can occur with pollen from Parthenium,Sunflower,Marigold deposited on the groundnut leaves that were clonized by the thrips

Symptoms:

• First appear on young leaves as necrotic lesions and vertical necrosis
• The necrosis later spreads to the petiole and stem. Necrotic lesions on the stem later spread upwards killing the bud.
• In some cultivators ,pods  harvested from the PSDN infected plants show necrotic lesions.

Management:

• Removal of weeds, particularly parthenum germinated with early rains is helpful in reducing PSDN incidence.
  
• Optimum plant population discourages thrips landing on the groundnut crop.
  
• Seed treatment with imidaclorprid (Gaucho 70 ws) indicate low thrips damage and subsequent low PSDN incidence