Darrell Blackwelder: The spider mite is tiny but hungry

Published 12:00 am Sunday, October 13, 2019

A few weeks ago, the yellow lantana at St. John’s Lutheran Church looked great.

The leaves were healthy, full of blooms and doing well. However, during the weeks of hot, dry weather, the plants looked horrible, almost overnight.

The plant’s decline was not due to lack of water or the excessive heat; the culprit was most likely spider mites. Spider mites are extremely small creatures less than 1 mm in size that feed ferociously on the underneath of plant leaves.

Their feeding habit makes the foliage yellow with a rust-like appearance. These pests are not insects but in the arachnid family (spiders). They are called spider mites because of the webbing that occurs underneath the leaves of the host plants. Mites become a pest usually during hot dry conditions experienced in September.

Mites are also serious pests for commercial strawberry, tomato and nurseries. There are several different species of mites varying in size and color. The most common in our area is the two spotted spider mite which can hatch in three days, becoming mature enough to lay eggs in five days.

Each female mite can lay up to 20 eggs per day with a life span up to four weeks. They are so light they can float in the air for miles. Mites can be controlled with pesticidal sprays. But in this situation, it’s a moot point to try and control them since the plants are nearing the end of their growing season.


Darrell Blackwelder deblackw@ncsu.edu is the retired horticulture agent and director with the NC Cooperative Extension Service in Rowan County.