Category: biopesticides

Insect viruses were isolated from many insect pests from different families to represent a potential alternative for chemical pesticides.

Viruses from families baculoviruses, cypoviruses, and densoviruses have been registered as biological control agents. Insect viruses are considered effective and environmental-friendly which may contribute to the achievement of sustainable agriculture goals through providing a suitable alternative to the chemical insecticides which have negative impacts on the environment and to the non-target organisms.

Insect Virus

As we all know, Helicoverpa armigera nuclear polyhedrosis virus (NPV) is a biological pesticide with good control effect, long-lasting efficacy, and no toxic and side effects to other organisms.

What is NPV?

Nuclear polyhedrosis virus is dodecahedron, tetrahedron, pentagonal, hexagonal, etc., with a diameter of 0.5-15uM. It embeds multiple virus particles and is composed of proteins, mostly in the blood, fat, chlorine tube, skin limbs, etc. of the host. It develops in the nucleus of cells, so it is called nuclear polyhedrosis virus. Nuclear polyhedrosis virus has a wide host range, mainly parasitizing Lepidopteran insects. Oral or wound infection. Viruses that enter the parasite through the mouth are digested by gastric juice, liberate baculovirus particles, enter the body cavity through the midgut epithelial cells, invade the cells, proliferate in the nucleus, and then invade healthy cells until the insect is lethal.

Insect feces and dead insects infect other insects, making viral diseases popular in pest populations, thereby controlling pest damage. Viruses can also be passed from eggs to insect progeny. Specialization is strong, a virus can parasitize one insect or its neighboring populations.

Insect virus — VPV series

The cotton bollworm (Helicoverpa armigera), belonging to Noctuidae, is one of the most destructive pest insects in agriculture worldwide.

It causes severe damage to plant crops, resulting in massive economic losses. Over the past decades, cotton bollworm has gradually developed resistance against almost all chemical pesticides.

As an effective biological agent (against cotton bollworm, Helicoverpa armigera nucleopolyhedrovirus has been exploited as a biopesticide to control pest insects. 

There are numerous soil-inhabiting nematode species, but not all are harmful to plants. This information sheet deals only with plant-parasitic nematodes. Within this group, some nematodes spend their life within the plant roots. These are endoparasitic. Others are ectoparasitic, and only their stylets (hollow spears used to puncture roots) enter the plant to extract nutrients from the roots or root cells. Plant-parasitic nematodes have many hosts and are seldom plant-specific.

Root knot nematodes

Root knot nematodes (Meloidogyne) are the most damaging species in the home garden. These nematodes have a very wide host range, affecting more than 2000 plant species worldwide. Root knot nematodes enter the roots as larvae, causing the plant roots to form galls or knots, and there may be excessive root branching. Underground organs such as potato tubers or carrot taproots may be damaged and become unmarketable. The nematode larvae mature in the roots, where they mate. The female adults enlarge, remain in the roots, and lay eggs into an egg sac that exudes into the soil. The eggs hatch and the young larvae go on to infect more roots.

Plants are damaged because the galls or root knots block the transport of water and nutrients through the plant. Nematode feeding sites in the roots can also provide entrance for other disease-causing organisms, like fungi or bacteria, leading to increased plant damage. Nematodes are a greater problem where conditions favour them, such as a long growing season, sandy soil and if plants are under water or nutrient stresses.

Root lesion nematodes

Although they are present in home gardens, where they can affect fruit trees, roses and turf, root lesion nematodes (Pratylenchus) are more damaging to broad-acre crops like cereals. Root lesion nematodes use the stylet to puncture roots and enter the cells. They move through the root, piercing cells, extracting cell contents, and leaving behind a trail of both cell-killing metabolites and eggs. Root cell death results in browning and lesioning of the roots. These lesions can rapidly coalesce, resulting in browning of whole roots. Individual lesions may fully encircle a root. These nematodes also damage feeder roots and root hairs, further reducing a plant’s effective extraction of water and nutrients from the soil. The overall effect is a weak, shallow root system with many dead or dying areas. When the soil dries out, root lesion nematodes become inactive and survive in a dry form in the soil or in root tissue of old crops. As the soil moistens, the nematodes become active again and reinfect the fresh roots of the new crop.

Bio-Nematocide： Paecilomyces lilacinus

Typical root symptoms indicating nematode attack are root knots or galls, root lesions, excessive root branching, injured root tips and stunted root systems.

Symptoms on the above-ground plant parts indicating root infection are a slow decline of the entire plant, wilting even with ample soil moisture, foliage yellowing and fewer and smaller leaves.

These are, in fact, the symptoms that would appear in plants deprived of a properly functioning root system. Bulb and stem nematodes produce stem swellings and shortened internodes.

Bud and leaf nematodes distort and kill bud and leaf tissue. In some cases, such as with SCN, yield loss may take place with no visible symptoms.

Bio-Nematocide： Paecilomyces lilacinus

A number of genera and species of nematodes are highly damaging to a great range of hosts, including foliage plants, agronomic and vegetable crops, fruit and nut trees, turfgrass, and forest trees.

Some of the most damaging nematodes are: Root knot (Meloidogyne spp.); Cyst (Heterodera and Globodera spp.); Root lesion (Pratylenchus spp.); Spiral (Helicotylenchus spp.); Burrowing (Radopholus similis); Bulb and stem (Ditylenchus dipsaci); Reniform (Rotylenchulus reniformis); Dagger (Xiphinema spp.); Bud and leaf (Aphelenchoides spp.); and Pine Wilt Disease (Bursaphelenchus xylophilus).

Bio-Nematocide： Paecilomyces lilacinus

The spread of nematodes from field to field usually involves farm equipment, contaminated plants or seeds, soil or mud transferred on the feet of people or animals, or surface water movement.

Various nematodes feed on all plant parts: roots, stems, leaves, flowers and seeds.

Bio-nematocide: Paecilomyces lilacinus

Nematodes are common soil pests that affect plants.

The aboveground symptoms of disease caused by nematodes can be difficult to detect, and may be often confused with symptoms of nutrient deficiency.

Typically, plants do not thrive, are paler than normal, and may wilt in the heat of the day.

Bio-nematocide: Paecilomyces lilacinus