MASS REARING TECHNIQUES OF INSECT BIO- CONTROL AGENTS
Asim Munawar1*, Aqsa Arshad1, Naeem Ahmed2, Shehbaz Sharif 1, Muhammad Waseem Shoukat3 Waleed Afzal Naveed1
1 Department of Entomology, University of Agriculture Faisalabad
2 Department of Agronomy, University of Agriculture, Faisalabad
3 Department of Plant Pathology, Bahauddin Zakariya University,Multan
Corresponding Author Email: [email protected]
Biological control or Biological Pest Control is a method of suppressing or controlling the population of undesirable insects, other animals, or plants by the introduction, encouragement, or artificial increase of their natural enemies to economically non–important levels. It is an important component of integrated pest management (IPM) programs.
In Pakistan work on biological control was started in 1956. When Common Wealth Institute of Biological Control (CWIBC) was established with Dr. M.A. Ghani as its first incharge, work was started on various projects of special interests.
Rearing Techniques.
Rearing of Chrysoperla carnea: Chrysoperla carnea adults are reared in a rectangular cage, made of 6cm thick, transparent plastic sheet. The cage is 35cm long, 35 cm high and 20 cm wide. Two circular windows, each of 13 cm diameters, covered with lids of the same material situated diagonally near opposite corners of a front wall of the cage are made for handling adults, as well as for cleaning sanitation and provision of water in Petri dish etc. Artificial foods containing yeast + sugar + honey + water (2:1:1:6) were provided in small food bowls, of 0.5 cm diameter, engraved in the upper side of two plastic rods each of 4 mm thick and 22 cm long, running width wise at the opposite ends inside the cage. A sieve of circular holes (2 mm diameter) is drilled into the sidewalls to ensure proper ventilation in the cage, for better survival and fecundity of adults; a black granulated paper underside the removable top of the new cage is a real substitute for the black sheet top as an oviposition substrate (Plate#1).
Plate#1. Rearing cage, Eggs and Adults
Rearing of Sitotroga cerealella: The Sitotroga cerealella culture is maintained on wheat grains under rearing chamber and also in glass jars. The jars are covered with muslin cloth. The adult are collected from the chamber every morning. After collection the adult of S. cerealella are kept in ovipositor jars containing starch for egg laying. The ovipositor jars remained for 24 hours on the starch and then the starch is sieved with 80 mesh sieve every morning and the eggs are collected in this method. The eggs passed another vials containing lid to remove all the contaminated materials with eggs such as insect body parts, starch and some other contaminated materials. After this the eggs are provided as fresh food to predators larvae/ adult stages and some eggs are put in another glass jars containing wheat grains for further propagation of the culture and the process is continued (Plate#2).
Plate#2. Rearing jars and rearing chamber for S. cerealella.
Rearing of Harmonia dimidiate. Harmonia dimidiata (Coleoptera: Coccinellidae) is reared in plastic containers of size 6x2cm. H. dimidiata are aphidophagous and usually feed on aphids. The aphid species Schizaphis graminum is cultured on wheat plant in glass house. Different stages of S. graminum are feeded to the adult and larvae of H.damidiata. H.damidiata adults are kept in rearing jars and aphid is provided as a feed on daily basis along with leaves of wheat. After week they start mating. Mating pairs are separated and placed in separate jars for egg laying. After 3-4 days of mating they started egg lying on wheat leaves. Eggs hatched nearly in 3-3.5 days at temperature between 25-26 °C and relative humidity about 20-21% (Plate#3).
Plate#3. Rearing jars, separate vials and adult H. dimidiate.
Rearing of Trichogramma chilonis: Mass rearing of Trichogramma requires first rearing of an insect typically specie of moth to produce eggs in which the wasp will develop. Several stored grain insects that can be easily reared on wheat, rice, maize grains or flour media have been successfully used. The most common lepidopterous insect hosts used for mass rearing of Trichogramma are:
(i) The Angoumois grain moth (S. cerealella)
(ii) The Rice meal moth (C. cephalonica)
First of all, we took the fresh eggs of S. cerealella and then glued them on card and placed that card into the jar of Trichogramma chilonis in lab where its culture is maintained. When adult of Trichogramma emerged it laid eggs in the eggs of S. cerealella and completely parasitized them (Plate#4).
Plate#4. Trichogramma chilonis parasiting the eggs
Rearing of Corcyra cephalonica Moth: Corcyra cephalononica moths are reared on rice grains inside the glass jars. Jars are covered with muslin cloth at the top. Whitish colored eggs were collected after 1-2 days. Eggs are collected on the upper side of the muslin cloth daily. Corcyra cephalonica is usually laying their eggs from inside the jars through their ovipositor outside the cloth. So these Eggs are used for parastization and feeding purpose. Mostly on trichogramma cards these eggs are pasted by glue and put in to trichogramma jars for egg parasitazation (plate#4).
Plate#4. Rearing jars for C. cephalonica
Conclusion:
It may not be an easy task to convince farmers to adopt a system approach to pest management and make greater use of biological control. In agriculture industry it is still dominated by pesticides, specific techniques within these approaches are constantly being developed and adopted to meet the changing needs of pest management. Biological control is expected to account for a well increased proportion of all crop protection methods by the year 2050.
