Which of the following is considered a pest?

The classification of a pest includes various organisms that can cause harm to crops and plants. Insects, nematodes, and diseases all fall under this category. Insects, such as aphids and beetles, are commonly recognized as pests because they can damage plant tissues, transmit diseases, and reduce crop yields. Nematodes, which are microscopic roundworms, can also negatively affect plant health by damaging root systems and disrupting nutrient uptake. Furthermore, plant diseases caused by pathogens like fungi, bacteria, and viruses can lead to significant loss in crop productivity and quality.

Since all listed options—sects, nematodes, and diseases—contribute to the deterioration of plant health and productivity, they are collectively recognized as pests. Therefore, stating that all of the choices are correct accurately reflects the broad spectrum of what may be classified as a pest in agricultural contexts. Understanding this helps to emphasize the importance of integrated pest management strategies that address all types of pests impacting crops.