Pest of Crop Plants and Their Natural Enemies

I. Introduction:

Insects and some vertebrates are labeled pests when these conflict with human interest or affect their welfare. The term pest is defined purely from anthropocentric viewpoint and really has no particular biological or ecological meaning. Damage by chewing pests are characterized by portions of crop plants eaten out as holes or mines in leaves, flowers, stems or fruits. Feeding damage by sucking insects and mites are indicated by spotted discoloration of plant parts. Sucking insects may also serve as vectors of some plant pathogens.

Pest species consume crop plants and they in turn are attacked by other organisms specifically parasitoids, predators or pathogens. These beneficial organisms that consume or kill pests of crop plants are generally referred to us as natural enemies.

II. Objectives:

1. To observe the feeding behavior and corresponding damage to crops of live insects with chewing and piercing - sucking type of mouthparts.

2. To familiarize with the common invertebrate and vertebrate pest species and their corresponding damage to major crops.

3. To observe feeding behavior of live predators.

4. To familiarize with the pest’s natural enemies.

III. Hypothesis

The feeding behavior of pests such as grasshopper, cotton stainer, mantids, and coccinellid beetle can become a serious problem to farmers.

IV. Discussion

The mouthparts of sucking insects are developed for piercing and sucking These pests damage plants by inserting their mouthparts into plant tissue and removing juices. Heavily infested plants become yellow, wilted, deformed or stunted and may eventually die.

Grasshoppers are considered as herbivores, which they prefer to eat green plants. Their heads are oriented downward that is perfectly positioned for the mouth to reach the leaves, stems, and flowers easily. Its chewing mouthparts called mandibles, move side to side with sharp, scissor-like edges and flatter surfaces for grinding their food. Other mouthparts called maxilliary palp or maxilla, act like spoons and forks to help handle the food. When there is scarcity with the food they eat, they become serious pests by migrating to other areas like farms and gardens.

Cotton stainers are currently noteworthy because of their presence on and occasional damage to fruits and ornamentals, particularly malvaceous plants such as Hibiscus spp. The feeding activities of cotton stainers on cotton produce a stain on the lint which reduces its value. The stain primarily is a result of the bug puncturing the seeds in the developing bolls causing a juice to exude that leaves an indelible stain. Feeding by puncturing flower buds or young cotton bolls usually causes a reduction in size, or the fruiting body may abort and drop to the ground.

Mantids are very efficient and deadly predators that capture and eat a wide variety of insects and other small prey. They have a "neck" that allows the head to rotate 180 degrees while waiting for a meal to wander by. Camouflage coloration allows mantids to blend in with the background as they sit on twigs and stems waiting to ambush prey. The two front legs of the mantids are highly specialized. When hunting, mantids assume a "praying" position, folding the legs under their head. They use the front legs to strike out and capture their prey. Long sharp spines on the upper insides of these legs allow them to hold to on their prey. The impaled prey is held firmly in place while being eaten. The spines fit into a groove on the lower parts of the leg when not in use .

Most beetles are herbivores, eating only plants. This includes roots, stems, leaves, seeds, nectar, fruits or even the wood of the plant itself. Prey includes fly maggots, earthworms, snails, grubs, slugs and even other species of beetles. Their mouthparts are used for penetration and feeding, and for boring holes for egg-laying.

V. Conclusion

In this research activity, it made me use my analytical skills and helped me widen my knowledge about the harmful effects of pests, particularly grasshopper, cotton stainer, mantids and coccinellid beetle. It can damage crop plants in which farmers can experience a total loss of crop yields. It should be be properly managed and controlled to maintain growing plants healthy.

References

Godawa, J. (2018). What Do Grasshoppers Eat? Retrieved from

https://sciencing.com/do-grasshoppers-eat-5655099.html

Mead F.W. (2017). Featured Creatures. Retrived from

http://entnemdept.ufl.edu/creatures/field/bugs/cotton_stainer.html

Watkins, G. (2019). Praying Mantids. Retrieved from https://entomology.ca.uky.edu/ef418

According to he Terminix (2020). What Do Beetles Eat? Retrieved from

https://www.terminix.com/blog/education/what-do-beetles-eat/

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