RK Patidar, P Dutta, V Kadam, M Pathak and RK Tombisana
Contd from last Saturday
· Capsule: Capsules prepared from wheat bran (5% w/w) with calcium alginate containing 1000-2000 nematodes/capsule are applied. About 70-80 capsules/plant could be used.
· Liquid baits: Desiccated nematodes (S.feltiae) are mixed with 56% sucrose solution (Georgis, 1990).
GUIDELINES FOR FIELD APPLICATION OF EPNS
EPNs always required sufficient moisture for their movement as well as to find their host. Generally nematodes are aerobic animals and they required adequate O2 for survival. The clay soils holds plenty of moisture but contains less oxygen with small pore space which may restrict nematode movement whereas in sandy soils, it must be irrigated to maintain the moisture into the soil. Nematodes should be applied to irrigated field, if possible irrigated to a depth of 10-12 cm. thus, irrigation is recommended for maintaining adequate moisture. Following points should be keep in mind during field application of EPNs:
A. Soil temperature at the time of application should range from 18-35oC.
B. Nematode should be applied to irrigated field and then should be again irrigated to maintain sufficient moisture.
C. Application should be done preferably during evening to avoid UV radiation and high temperature.
D. Sometime application need to be repeated for insects like white grub.
E. Flood jet nozzle is fairly effective for spraying, as it spray more number of nematodes/unit of area.
CLASSICAL EXAMPLES OF FIELD EFFICACY OF EPNS
EPNs belongs to the families of Steinernematidae and Heterorhabditidae and have tremendous potential as alternatives to chemicals moreover act as important biological control agents, who have the capacity to actively search and infect host larvae in the soil. The field efficacy of EPNs cab be comprehend with the following examples:
1. Infestation of Mole cricket (Scapteriscus sp.), 74.8% was control by releasing in field trial of S.scapterisci in Florida at the application rate 2.5 x 109 IJs ha-1. Late stage nymphs and adult mole cricket were found to be highly susceptible to the nematodes.
2. Sugarcane root stalk borer (Diaprepes abbreviator) and blue green weevil (Pachnaeuslitus) and nematodes S.carpocapsae, S.glaseri and H.bacteriophoraare added to irrigation system, resulting in a 72% reduction of emergence of Diaprepes abbreviator and Pachnaeuslitus adults.
3. In Hawaiian field trials, an average of 87.1% larval mortality of the Mediterranean fruit fly (Ceratiriscapitata) was observed following application of S.carpocapsaeMaxican strain at 5000 IJs cm-2 of soil.
4. In India, work on EPN was first initiated by Rao and ManjuNath, who demonstrated the use of DD-136 strain of S.carpocapsae in the control of insect pests of rice, sugarcane and p apple.
The writers are from the College of Post Graduate Studies in Agricultural Sciences, CAU (I) Umiam, Barapani, Meghalaya
For further details contact: - Public Relations & Media Management Cell, CAU, Imphal. Email: [email protected]