Heat is bringing out the bugs

Univ. of Md. Extension personnel report that the recent warm temperatures are causing some pest populations to escalate. Thrips are being found in greenhouses on just about all plants. Thrips damage symptoms include white streaks on flowers and speckling on foliage. Growers are advised to do tap tests of flowers and foliage onto white paper to see if thrips are present.
Spider mites, which thrive in hot, dry environments, are building up on monarda, buddleia and zinnias. Look for yellow speckling on the foliage. Webbing will also be present on the foliage if populations are high.
Fungus gnats are causing vinca and dahlia plants to collapse by feeding at the base of plants. Inspect stems for translucent larvae with black heads. Monitor for the larvae by placing potato disks on the substrate surface and checking them regularly.