Which leafhopper species is known for causing yellowing and reduced vigor in alfalfa?

• A. Colorado potato beetle
• B. Alfalfa weevil
• C. Soybean aphid
• D. Potato leafhopper

Answer: (D)

Potato leafhopper is known for causing yellowing and reduced vigor in alfalfa because it feeds by piercing and sucking sap from the plant, and its saliva disrupts the plant’s water and nutrient flow. This feeding produces hopperburn, a yellowing and scorching of new growth that looks like the plant is stressed or dying, especially in hot, dry conditions. The insect is small and pale green, and it campaigns into alfalfa fields in spring and summer, targeting tender growing tips where damage hits yield hardest. In contrast, the other insects listed are not typically associated with this specific yellowing pattern in alfalfa: the Colorado potato beetle is a potato pest that defoliates potato leaves, the alfalfa weevil mainly causes general defoliation rather than the characteristic yellowing, and the soybean aphid is a soybean pest whose damage presents differently.