संग्रहित अनाज के कीट-पतंग तथा उनका प्रबंधन

Global loss in stored products, caused by insects, have been estimated to be between five and ten percent. In the tropics it may reach upto 30%. Insects not only cause direct loss through consumption of kernels but also indirect losses which includes accumulation of frass, exuviae, webbing and insect cadavers. High levels of this insect detritus may result in grain that is unfit for human consumption. Storage insect pests are categorized into two types viz.,

1. Primary storage pests

Primary storage pests are those capable of penetrating and infesting intact kernels of grain, and have immature stages that can readily develop within a kernel of grain. 

2. Secondary storage pests

Secondary storage pests cannot infest sound grain but feed on broken kernels, debris and grain damaged by primary insect pests. In general, the immature stages of these species are found external to the grain. 

The integrated pest management (IPM) approach for stored grain includes:

1. Sanitation:

• It should be maintained at both field and storage godowns.
• Undergo clean harvest.
• Both harvesting and threshing machines need to be thoroughly cleaned prior to use.
• Never store a new crop along with the old grain.
• Cracks and crevices should be properly sealed
• Remove spilled grain outside the storage structure.
• Rat burrows to be closed with a mixture of broken glass pieces and plastered with cement.
• For additional protection, the inside and outside surfaces, foundations and floor of a storage facility should be treated with a residual insecticide, four to six weeks prior to harvest.
• The grain is monitored every 2-3 weeks during throughout storage period
• careful monitoring should  be done on the following parameters:Aeration is used to dry and cool the newly stored grain there by prevent the development of hotspots. It is also used to prevent moisture migration when ambient temperatures drop below that of the grain temperature.
  • Grain quality
  • Grain temperature
  • Insects and insect density
  • Hot spots
  • Mould growth
  • Any “off odor”

2. Frequent monitoring:

Pest monitoring is an important component in the post-harvest IPM practice for stored grain

3. Aeration

Proper aeration in stored grain controls humidity and reduce the possibility of pest infestation

4. Pesticide treatments

Infestation develops due to hidden or cross infestation, which could be effectively managed by using the following insecticides and fumigants.

Grain protectants: it is not advisable to mix the chemical dust along with food grains as it is meant for human consumption. However, they can be mixed with the grains meant for seed purposes only. Pyrethrum dust, Spinosad dust etc. are normally used as seed protectants.

Fumigants: Properly conducted fumigation will stop insect infestation and effectively reduce the pest populations.

Aluminum phosphide: This is a most widely used fumigant in India and available in the market under trade name Celphos of 3 gm tablets. The phosphide pellets or tablets release phosphine gas as they are exposed to moisture in the air. The recommended dose is 3tablets/tonne of grains.

Reference:

TnauAgritech Poratal - http://agritech.tnau.ac.in/index.html

David¸B.V and Ramamurthy, V.V. 2012. Elements of economic entomology. Book Chapter: Insect pests of Stored grain Products.

Authors:

Guru Pirasanna Pandi G., Soumia P.S. and Thava Prakasa Pandian R.

Ph D Scholars, Indian Agricultural Research Institute, New Delhi.

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