CDFA Pest Prevention Plant Regulation Practice Exam

In which stage does the Japanese Beetle cause damage?

1. the larva stage only

2. the adult stage only

3. in both stages

The correct answer is: in both stages

The Japanese Beetle causes damage in both its larva and adult stages, making this the correct choice. During the larval stage, commonly referred to as grubs, these beetles primarily feed on the roots of grasses. This feeding can lead to serious damage in lawns and agricultural fields, as the weakened plants may not be able to absorb enough nutrients and water, potentially resulting in patches of dead or dying grass. In their adult stage, Japanese Beetles become more visible and switch their diet to the leaves, flowers, and fruits of a wider variety of plants, including ornamental plants, fruit trees, and vegetable crops. Their feeding leads to significant defoliation and can compromise the overall health and productivity of the affected plants. By causing damage in both life stages, the Japanese Beetle presents challenges that may require comprehensive pest management strategies to mitigate their impact effectively.