LEC 4.pptx
- 1. By Farjana Rauf Asst. Prof., Dept. of Seed Science and Technology, BAU, Mymensingh
- 2. General management of stored product insects: Although, insect management options like physical, mechanical, biological and chemical practices are available, fumigation was practiced since long time in storage. Some of the general preventive and curative management options are listed below.
- 3. Drying of the grains to a moisture range of 10 to 14% based on grain type, avoid majority of the damage. Drying can be done under sunlight or using any developed dryers. After harvesting of the grains before shifting to storage, certain measures have to take the initial infestation or inoculum of storages pests. Some of the preventive measures are listed below, Sanitation of storage site is prerequisite, which involves removing of dirt, debris, foreign particles, other insects and infested grains that will reduce avoid initial infestation.
- 4. Handling of grains should be proper and the storage structure should not be damaged. Proper stacking size and wooden dunnage should be maintained to avoid from mechanical damage or to keep away from wall. Between each stacks a proper space should be maintained. Sometimes the initial infestation observed in field can be managed with exposing the grains for sunlight for shorter period. Using of improved storage structures. In Indian conditions grains are storing variedly from small metal bin to bulk storage in gunny bags under warehouses. Hermetic storage concept developing can be exploited for the future. Jute bags are generally using, which are additionally suggesting to amalgamate with polythene lining.
- 5. Newer lots have to store separately and should have isolated distance between old stocks. Several improved bins are available, which are developed by different institutes for Indian conditions like, Pusa bin, PAU bin, TNAU bin, etc. can be used. Disinfestation of bulk and bag storage structures using insecticides is also an important practice to be done prior to storage and a layer of insecticide spray can be suggested immediately after storage. Since, dichlorvos was banned using in warehouses, presently deltamethrin and malathion are the available options for disinfectant and for surface sprays.
- 6. 1. Temperature management: Increasing or decreasing the temperature can alter the insect growth and metabolism. Optimal temperature for most of the storage insects is between 25 and 33º C. deviations from these points will slower down the growth and continuously to death. Passing of dry or wet heat in the storage system or refrigerated aeration yield better results. Even it can be achieved using high frequency waves.
- 7. 2. Mixing of inert dusts: Inert dusts like clays, sand, ash, minerals, silica (silicon dioxide) are effective in managing the insects by moisture loss of the insect body by abrasion.Dusts that contain natural silica, such as diatomaceous earth (DE), are commercially available and using in many developing countries either to manage or to improve fumigation efficiency.Activated clay (kaolin) has also been used in protecting grains from the attack of storage insects.
- 8. 3. Irradiation: Radiations in lower dose can able to kill or sterilizes the common grain pests, and even the eggs deposited inside the grains. Radiations like microwaves, xrays, etc. are utilising in several forms to treat the grains before storage to disinfest them. 4. Use of controlled atmosphere: A novel methodology where the storage atmosphere generally contains 78% Nitrogen (N2), 21% Oxygen (O2) and 0.03% carbon dioxide (CO2). This proportion can be altered mechanically by altered atmosphere which interfere with the normal insect metabolism which achieve mortality.
- 9. 5. Mechanical devices, traps, etc.: Devices developed for monitoring and mass trapping such as entoleters, which are using in flour mills. TNAU under AICRP on Post-Harvest Engineering & Technology has developed different types of insects traps (TNAU stored insect kit). Apart from these some other traps like Probe trap, Pulse Beetle Trap, Light traps, Sticky traps, Bait traps and Pheromone were also developed and tested in some of the countries.
- 10. b. Biological control: 1. Semiochemicals: Much of the behavior of insect pests of stored products is associated with the search for food, sexual partners and egg-laying sites, together with defensive activities to protect them from adverse environmental conditions and natural enemies. This behavior is modified by chemical signals produced either by the insects themselves or by other organisms including the plants upon which they feed. This includes pheromones and allelochemicals. Insect traps are available for some of the insects like flour beetles and lepidopteran insects.
- 11. 2. Botanicals: Plant extracts or products having insecticidal properties like Neem leaf powder, black pepper, turmeric powder, Sweet Flag Rhizome powder etc were also proved their effectiveness in amangingthe stored grain pests. General dosage is 10g / kg of grains should be mixed. Different formulations like tablets, pellets, oils, etc are developing and are required commercialisation. 3. Biopesticides: Some of the commercially available entomopathogenic fungi against field crop pests like Beauveriabassiana, Metarhiziumanisopliae and bacterium – Bacillus thuringiensis (Bt) were tested majorly against stored-grain pests especially beetles.
- 12. c. Chemical management: In India, fumigation using phosphine is the only available option as methyle bromide was phased out. Aluminium phosphide (Alphos, Celphos, Phosphume, Quickphos, etc.) recommended for cover fumigation @ 3 tablets of 3 g each per tonne of grain, for shed fumigation @ 21 tablets of 3 g each for 28 cubic metres. 5 to 7 days, the fumigation should be done and made leakage proof. Sand snakes are used in case of cover fumigation. Nowadays , precipitate silica is also used against stored pests.