Pacer (Metarhizium Anisopliae)

Conidial penetration: The conidial spores of Metarhizium anisopliae gets attached to the host by entering through the hosts spiracles and pores of its sense organs and start germinating. Surface growth on cuticle occurs to a limited extent where the fungus derives nutrition from the lipids in the cuticle. The fungus produces an appressorium (a swelling on the end of the germ tube) which marks the start of invasion of insect. The appressorium produces a penetration peg that enters the external skeleton (cuticle) of the host. The fungus produces a lateral extension of hyphae inside insect body which proliferate and start feeding on insects internal contents.

Enzyme production: Metarhizium anisopliae has extracellular enzymes mainly the proteases which help in penetration of insect cuticle through localized hydrolysis. Its mycelia produce secondary metabolites and destruxin- a mycotoxin cyclodepsipeptide that helps the fungus overcome the host defenses as the host tends to produce melanin, a dark compound as a defense mechanism

Growth: Metarhizium anisopliaes hyphae continue to grow till mycelia fills the entire insects body. After consuming internal contents (haemolymph) the fungus breaks out of insects cuticle and starts sporulating making the insect appear fuzzy. After its death the host is seen to be enveloped by a mat of green conidia. Metarhizium anisopliae infects the insect on contact and does not need to be consumed by the host to cause infection.

Environment factors: Metarhizium anisopliae is sensitive to temperature extremes. The spore viability decreases as storage temperatures increase and virulence decreases at low temperatures. The fungus needs high humidity for releasing and multiplication of spores.

Infection establishes between 24 to 48 hours. The infected insect may live for three to five days after hyphal penetration and after death of host insect pest, the conidiophores bearing conidia are produced on cadaver.

Metarhizium anisopliae has a unique Horizontal Transfer Effect (HTE) unlike any chemical termiticide. Normal chemical termiticides when drenched in soil enter mostly vertically down in soil and partially horizontally. Only the termites coming in direct contact with the chemical termiticide get killed without affecting the large travelling colony. However, Metarhizium anisopliae being a Biotermiticide has a Horizontal Transfer Effect starts multiplying horizontally due to availability of moisture and target the pests by killing it.

Benefits:

• Pacer effectively controls economically important soil pests like root grubs, termites, ants and locusts
• Pathogenic pest load reduction leads to improved plant health and thereby increased crop productivity
• Pacer can be used as an effective component in Integrated Pest Management (IPM) programmes, thereby leading to a reduction in use of chemical pesticides and creating a safer environment