Paecilomyces lilacinus was first discovered in 1966 where it was found to be associated with nematode eggs. Subsequently it was found parasitizing the eggs of Meloidogyne incognita ( Root knot nematode ) in Peru.
Mode of action …
Conidial penetration : Paceilomyces lilacinus on getting attached to the host forms a dense mycelium that gives rise to conidiophores. These bear phialides at the ends of which spores are formed in long chains. 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 skin (cuticle) of the host. The fungus produces hyphae inside insect body which proliferate and start feeding on insect’s internal contents.
Enzyme production : Paceilomyces lilacinus produces a serine protease that is toxic to Meloidogyne spp eggs It also produces proteases and chitinase enzymes that weakens nematodes so as to enable a narrow infection peg to be established and push through the insect’s exterior and pathogenise it from within.
Growth : Once inside, Paceilomyces lilacinus replicates and consumes the nematodes’ internal organs and blood-like fluid, the hemolymph eventually killing it. It infects the nematode on contact and does not need to be consumed by nematode to cause infection.
Environment factors : The rate at which it kills the nematode is dependent on temperature and humidity. High humidity is essential for conidial germination and infection establishes between 24 to 48 hours. The infected nematodes may live for three to five days after hyphal penetration and, after death of nematode, the conidiophores bearing conidia are produced on cadaver. The fungus is specific to Nematodes. Nematodes die before the fungus is visible. Paecilomyces lilacinus grows best at 20-30 degree C and at a relative humidity above 65%.
Target Pests : Root-knot nematode, Remiform nematode, Cyst nematode, Golden cyst nematode , Citrus nematode and Lesion nematode.
This process shows root-knot nematode parasitism …
Root-knot nematodes live in the soil and hatch from eggs, then navigate to roots. They attach themselves at the base of the plants vascular system near the root tip and give up their mobile lifestyle as they feed off the plant and swell. The cells that the nematode (N) attaches to become giant cells (GC) through a complex process. The phloem (Ph) and xylem (Xy) form cages around the giant cells with many connections that allow the transfer of nutrients and water into the giant cells. The nematodes, in turn, are connected via their mouth parts to the giant cells so have a ready supply of food and water. Eventually these structures swell and are visible by the naked eye as galls on the roots. The lucky nematode feeds till laying eggs which will continue the life cycle of the respective species.
Click … “How nematodes damage the crops … “
Treatment : Fungi Paceilomyces lilacinus
Effective viable count : 100 x 108 cfu/gm
10~20gm / 20 Liters
( Activate the mixture with same amount of molasses > 2 hours for better result )
Avoid mixed with any fungicide.
Avoid high temperature, moisture and direct sunlight in storage