Potentials of Biocontrol Agents in Insect Pest Management
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Potentials of biocontrol agents in Insect pest management Dr.S.Sridharan, Ph.D Professor (Agrl.Entomology) Dr.P.A.Saravanan, Asst. Professor Department of Agricultural Entomology Tamil Nadu Agricultural University Coimbatore -641 003 CHEMICAL IPM OR BIOLOGICAL IPM? In light of mounting concern with products of biotechnology, preservation of biodiversity, food safety and global food trade issues, TRUE BIOLOGICAL IPM implementation will assume an even greater role in 21st Century agricultural systems. History of Bio control in TamilNadu • The work on biological control in Tamil Nadu started as early as 1926. In 1926, Dactylopius tomentosus (Lamarck) was brought to Tamil Nadu from Sri Lanka for the control of the Opuntia cacti. Within 20-30 years, the weed was completely brought under control. • During 1929 and 1930, Vedalia beetle Rodolia cardinalis (Mulsant) was brought to Tamil Nadu from California and Egypt and mass multiplied for large scale release in Nilgris against cottony cushion scale, Icerya purchasi Mask. Within a year, the pest was effectively checked. • During 1989-1994, TNAU received major projects from the Department of Biotechnology for Biological control research on Trichogramma, Chrysoperla, Crptolaemus, NPV of Helicoverpa armigera (Hubner) and NPV of Spodoptera litura Fabricius under the Pricipal Investigatorship of Dr.S.Jayaraj. • During 2002, an invasive pest, sugarcane wooly aphid devastated the sugarcane crop and caused very heavy loss. The pest was effectively controlled within a period of 1-2 years by the activity of predators, Dipha aphidivora (Meyrick) and Micromus igorotus Banks and a parasitoid Encarsia flavoscutellum Zehntner • The share of bio pesticides has slowly increased from < 1 % to 4.2 % in 2011-2012 which is expected to increase at the rate of 10 % annually. • Currently 20-25 bio pesticide products have been registered and used in India. • Our recent experience on the classical biological control of invasive papaya mealy bug with the parasitoid Acerophagous papayae is an excellent example for the potentials of biological control agents in containing the pest successfully. Trichogramma - Egg parasitoid • Trichogramma are the most widely augmented species of natural enemy, having been mass-produced and field released for almost 70 years in biological control efforts. • Worldwide, over 32 million ha of agricultural crops and forests are treated annually with Trichogramma spp. in 19 countries, mostly in China and republics of the former Soviet Union (Li 1994). Biology Egg period – 1 day Larval period – 3 to 4 days Pupal period – 4 to 5 days Total life cycle – 8 to 10 days Adult longevity – 6 to 8 days • 1 to 10 eggs / day or 10 to 190 eggs during her life • No. of eggs laid per host egg 1-20 or more • Parasitized eggs turn black after 3-4 days Materials needed for Trichogramma production Target pests of T.chilonis • Sugarcane internode borer • American boll worm • Pink boll worm • Spotted boll worm • Citrus caterpillar • Pomegranate fruit borer • Rice leaf folder Target pests of T.japonicum . Sugarcane top borer . Rice yellow stem borer Bollworm egg parasitized by Trichogramma (left) and egg shell remaining after bollworm caterpillar has hatched Anar butterfly eggs- healthy parasitized and egg shell Bracon brevicornis • Gregarious ecto larval parasitoid of many lepidopterans • Indirect control by paralyzing the larvae Hosts Antigastra cataluanalis Adisura atkinsoni Earias sp H.armigera Noorda moringae Opisena arenosella P.gossypiella C.partellus etc Biology 25 eggs / day / larva Egg period – 28 to 36 hrs Larval period – 4 to 7 days Pupal period – 3 to 6 days Adult longevity – 15 to 40 days Fecundity – 150 to 200 eggs Egg laying up to 10 days,2 day old adults at 5 degrees celcius and 50-60% RH for 30 days Goniozus nephantidis • Promising ecto larval parasitoid of coconut black headed caterpillar Biology Total Life cycle – 10-14 days. Fecundity – 20 – 50. Parasitize 6 – 7 Larvae Adult Longevity – 15 – 30 days Cryptolaemus montrouzieri . Australian lady bird beetle . Controls coffee green scale, whitefly, aphids, mealybugs . Break through in applied classical biological control Biology 30 days life cycle Premating period – 5 days Oviposition period – 10 days Eggs – pale yellowish white Incubation period – 5 to 6 days Grub –pale greyish with white lines, sluggish initially Grub period-20 days-four instars Wax strands on grown up grubs - defensive mechanism Pre pupal period – 2 to 4 days Pupal period – 7 to 9 days Longevity – 50 to 60 days Fecundity – 200 to 220 eggs Biology Egg period – 3 to 4 days Larval period – 8 to 10 days Three instars - third instar has a length of approximately 0.8 mm and eats up to 50 aphids per day Pupal period – 5 to 7 days Preoviposition period – 3 to 7 days Egg laying from 5th day onwards Peak period – 9 to 23 days after emergence Male longevity – 30 to 35 days Female longevity – up to 60 days Fecundity – 600 to 800 eggs / female.