Nematode management

Nematodes affecting Banana and their control:

Out of more than 100 species of Nematodes, the following ones are found to be more destructive and widely distributed affecting Banana:

• Burrowing nematode
• Root-lesion nematode
• Root knot nematode
• Spiral nematode
• Cyst nematode
• Reniform nematode 

These nematodes invade, feed and reproduce in the roots and rhizomes of banana. The destruction of the roots and corm tissues reduces water and mineral uptake which results in reduction of plant growth and development. The nematodes spread from one locality to another through planting material as well as through water that drains from infected areas.

The occurrence of nematode problem, particularly 'Root knot nematode', is more severe in Tissue Culture Banana seedlings than in conventional planting materials. The symptoms of nematode infection in TC plants can be observed in the secondary hardening stage itself and the reason is said to be untreated soil used as potting mixture in that stage. Heavy nematode infested Tissue Culture seedlings, which were not properly taken care of by some biotech companies and subsequently sold to gullible farmers, failed to establish in the main field after planting.

Symptoms:

• Red/Black lesions on the roots and decaying of roots.
• Infected plants have much lower number of secondary and tertiary roots. 
• Stunted growth of plants (Plants exhibit poor health).
• Yellowing of leaves. Foliar symptoms of nematode damage are mostly similar to the conditions attributed to water logging, weed competition, nutrient deficiency Etc.
• Affected plant may bear small bunch or choked bunch. 
• The infested plants also topple over and uproot easily during wet and windy weather because of inadequate anchorage.
• Prolonged duration of the crop.

Nematode infested banana plant - Pic. Courtesy : NRCB, Trichi.

 

Control:

• Use of nematode free planting materials is an important prophylactic measure to control nematodes.
• Summer ploughing suppress the nematode population.
• Use only fully composted manure and avoid partially composted manures.
• Increased use of green manure and other organic amendments.  
• Use of press-mud in the field is also useful.
• Eliminating weeds which are hosts to the nematodes.
• Crop rotation with Paddy, Sugarcane and Sunhemph suppress the nematode population.
• Cultivation of antagonistic  plants (plants acts as a repellent for nematodes) of Marigold namely Tagetes erecta and Tagetes patula (Tamil: Sendu malli, Sevanthi and Thulukka Samanthi) as an intercrop in banana bed.
• If the planting material is the conventional 'Suckers', then complete disinfection can be achieved by paring followed by dip in Monocrotophos solution at 0.5% for 30 minutes and shade drying for 72 hours before planting.  
• For the production of nematode free healthy TC planting material, the biotech companies have to first fumigate the potting mixture used for secondary hardening stage. If the symptoms are noticed during the secondary hardening period, it is advisable to apply  Carbofuran 3G (Furadon) @ 10 gm in each poly bag containg the plant. Usage of soilless growing media like 'Jiffy' pots/bags is also a viable option.
• Application of Neem cake 500 grams / plant at the time of planting and 1 kg/plant 3 months after planting.
• Rake the soil around the pseudostem and apply Carbofuran 3G (Furadon) @ 10 gm per plant during planting and 25 gm per plant during 3^rd and 5^th  of planting will control the infestation. In the fields where Nematode infestation is rather high, it is advised go for a total of 80 gram of Carbofuran 3G/plant in not less than 4 split doses. 

(OR) 

Apply newer nematicides like Rugby10G (Cadusafos 10G) @ 10 gram/plant or Caldan4G (Cartap hydrochloride 4G) @ 10 gram/plant, one at the time of planting and second by 3rd MAP (Months After Planting) for a successful control of the nematode populations. The cost benefit ratio worked out to be much cheaper in the above mentioned newer nematicides when compared to Carbofuran3G.
Some farmers of Theni district, Tamilnadu are applying different nematicides  for each application say Carbofuran in I dose, Thimet in II dose and Caldan for III dose and the results are found to be excellent.

• Nimbicidine  or Neemgold  @ 1.5%  - 30 ml for small plant and 1 litre for bigger plant is also effective. 
• As a bio-control measure, Paecilomyces lilacinus @ 25 gm per plant has also proved very effective in controlling nematodes. Addition of Trichoderma viridi 25 gm/plant, VAM 50 gm/plant  and Pseudomonus fluorescens 25 gram per plant will give very good results. See the link for biotech remedial measures.

Courtesy: NRCB, Trichy.

 Regards,

A.Vishnu Sankar