Nematodes in insect control

Nematodes, non-segmented animals ranging between 0.1mm and several meters in length, are also referred to as round-, eel-, or threadworms because of their usually cylindrical and elongate body shape. They have digestive, reproductive, muscular, and simple excretory and nervous systems but lack circulatory and respiratory systems.

Many nematode species are associated with insects and the types of relationship range from phoresis to parasitism and pathogenesis. Nematodes that have parasitic associations with insects have been described from 23 nematode families. Seven of these families contain species that have potential for biological control of insects:

1. Mermithidae and Tetradonematidae (Order: Stichosomida);
2. Allantonematidae, Phaenopsitylenchidae, and Sphaerulariidae (Order: Tylenchida)
3. Heterorhabditidae and Steinernematidae (Order: Rhabditida).

Presently, only the Heterorhabditidae and Steinernematidae are used as microbial insecticides and are produced commercially by various companies around the world.

The pioneers in Invertebrate Pathology

1. Agostino Bassi
2. Louis Pasteur
3. Elis Metchnikoff

(Steinhaus, 1956,1975)

Bacillus thuringiensis (Bt)

Bacillus thuringiensis (Bt) 

Extensively for control of arthropods due to:

1. High virulence
2. Low cost
3. Ease of application
4. Narrow host specificity

Defining biological control

The use of living organisms to suppress the population of a specific pest organism, making it less abundant or less damaging than it would otherwise be (Eilenberg et al., 2001).

Based on the 1919 (Smith, 1919) definition of biological control, one of the original descriptions, biological control agents (including parasites, predators, and pathogens) should provide self-sustained control with density-dependent responses to host populations.

‘biopesticides’

What is the meaning of biopesticides? Bio means life and pesticides can be defined as a chemical used to kill pests (as rodents or insects). Microbial agents are often referred to as ‘biopesticides’ and have been very successful in the field of biological control.