What characteristics make Helicoverpa a pest?
To determine what attributes that make Helicoverpa as a pest, the answers lie in the following: how an insect (in this case, Helicoverpa spp.) becomes pest, geographical distribution, affected host plants, and biology and life cycle of Helicoverpa spp.
Gullan and Craston (2011) clearly explained on insects may become pests and these are based on the following reasons:
1. The introduction of insects into area which is outside their native range. Once the insects established themselves in the newly-introduced area with suitable habitat as well as absent of natural enemies, there will be a ‘population explosion’ and the insects will gradually become pests.
2. Insects may become pests when they are become vector of a plant, carrying plant pathogens such as virus or bacteria. When they infest a crop, then the crop will be affected with disease carried by the insect.
3. Host-switching may cause the insect to become pest when the insect switches from its natural diet to new ones. Host switching is common to oligophagous insects (insect that feeds on few kind of plant species) and polyphagous insects (insect that feeds on wide range of plant species). Due to this, some insects have more host plants, causing them to pose serious damage to more crops.
4. Introduction of large scale monocultures causes the rise in insect population, especially those insects feed on that particular crop.
5. Poor planning of farming practice can cause insects to become pests. When there is no crop rotation, there will be ‘no break’ in between the life cycle of the pest.
Gullan and Craston (2011) clearly explained on insects may become pests and these are based on the following reasons:
1. The introduction of insects into area which is outside their native range. Once the insects established themselves in the newly-introduced area with suitable habitat as well as absent of natural enemies, there will be a ‘population explosion’ and the insects will gradually become pests.
2. Insects may become pests when they are become vector of a plant, carrying plant pathogens such as virus or bacteria. When they infest a crop, then the crop will be affected with disease carried by the insect.
3. Host-switching may cause the insect to become pest when the insect switches from its natural diet to new ones. Host switching is common to oligophagous insects (insect that feeds on few kind of plant species) and polyphagous insects (insect that feeds on wide range of plant species). Due to this, some insects have more host plants, causing them to pose serious damage to more crops.
4. Introduction of large scale monocultures causes the rise in insect population, especially those insects feed on that particular crop.
5. Poor planning of farming practice can cause insects to become pests. When there is no crop rotation, there will be ‘no break’ in between the life cycle of the pest.