Nurseries should be scouting poly-houses for pest problems

Recent heat waves have given insects a jump-start this spring, so pest problems we usually don’t see until early May could happen in the next two weeks. Nurseries will find insects in the poly-houses and container holding areas much earlier than usual.

In poly-houses, watch for outbreaks of aphids by looking for the cast skins (like dandruff), check for spider mites by looking for stippling and yellowing of infested foliage, and look for broad mites by being alert for new shoots that turn black. Check suspect infestations of spider mites by placing a white piece of paper under branches and rapping the branch sharply over it, dislodging mites onto the paper. Broad mites are too small to see without a microscope, so send samples to MSU Diagnostic Services to confirm infestations. The following insecticide products can be used when damaging infestations are found.

Systemic insecticides

Marathon, Tristar, Flagship, Safari, or Aria can be used as a soil drench to prevent problems with whiteflies, aphids, mealybugs or soft scales.


Aphids: Aria, Azatin, Benefit, BotaniGard, Decathlon, Discus, Distance, Endeavor, Enstar II, Flagship, Kontos, Marathon, Ornazin, Orthene 97, Precision, Safari, Tame, Talstar, Tristar.
Spider mites:
Akari,Avid, Floramite, Hexygon, Judo, Kontos, Ovation, ProMite, Pylon, Sanmite, Shuttle-O, Tetrasan.
Broad mites:
Avid, Akari, Judo, Pylon, SanMite.

Broad mites

Broad mites are less than 0.3 mm (smaller than a period in font size 12 print).

New Guinea impatiens.
New Guinea impatiens Photo Credit:Leanne Pundt

Saliva Photo Credit: Leanne Pundt

Broad mites

Evolution Broadmites.
Evolution Broadmites

Broad mite symptoms

Sweedish Ivy distortion
Swedish Ivy distortion of leaf edges

Azalea downward curling of leaves.
Downward curling of leaves


Green peach aphids.
Green peach aphids.

Foxglove aphid.
Foxglove aphid.

Spider mites


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