New App for Nursery and Landscape Pest Management

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The Southern Nursery IPM Working Group (SNIPM), of which several faculty at NCSU are members, has just released and exciting new App available for iPhones and Android phones.  The App predicts the emergence of arthropod, disease, and weed pests based on degree day estimates, provides diagnosis help, and even pesticide recommendations.  This is a very comprehensive tool that should prove valuable to industry and extension personnel.  A complete description can be found on the website http://www.ipmproapp.com/.

Wax Scale Eggs Hatching

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Indian wax scale eggs are hatching now on campus.  We find these most often on

Wax scale on the twig of a nursery-grown maple. Photo: S.D. Frank

evergreen broad leaf plants such as cherry laurel. However, they are very generalist and can be found on over 50 plant species including deciduous trees like the maple tree pictured. A systemic insecticide is best for these and most scale because they are very well protected from contact sprays.  More information and management recommendations here.

Crape myrtle aphids conserve predators

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Crape myrtle aphids are around every year and very rarely get out of hand enough to

Adult crape myrtle aphid. Photo: S.D. Frank

warrant insecticide treatment.  Although on the most stressed trees or those tended by ants we have seen severe damage on occasion.  Regardless, natural enemies frequently keep these aphids from getting out of control.  I feel the aphids are actually a good thing to have because they attach and support predators in your landscape without causing much damage to trees.  These and other innocuous herbivores are important for conserving natural enemies so don’t go after them unnecessarily.  Remember, no herbivores = no natural enemies.  Another interesting thing about this aphid is that no natural enemies are know to parasitize it.  It is not native to the US (of course neither is its host) but efforts in it home range have also not turned up parasitoids.

Euonymus scale crawlers are back!

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On my way to work today I found a great infestation of euonymus scale on my friend’s

White male euonymus scales and tiny orange crawlers. Photo: S.D. Frank

hedge.  Euonymus scale has 3-4 generations per year in NC and this year I would bet on four since they got an earlier than usual start.  Regardless crawlers are active now which makes it a great time to treat.  But be careful, we have found many species of predators and parasitoids actively feeding on euonymus scale the lacewing larva in this video.  In addition, pyrethroid insecticides can cause significant harm to these predators which allows scale and other pests to live predator free.  Remember, scales live inside water-proof wax covers that protect them from contact insecticides.  Predators and parasitoids do not. For more information and management suggestions check here.

Thrips in greenhouses: early and abundant

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Many growers are experiencing thrips abundance and damage that is greater and earlier than usual.  This is likely because we had a mild winter and most plants and plant pests are ahead of schedule this year.  To get thrips under control will likely take 3 applications of insecticide 5-7 days apart.  This initial round of applications could be done with a single chemical but rotate to a new chemical with new mode of action for subsequent applications. Since many plants are starting to bloom we have several chemicals that are generally not phytotoxic to foliage or flowers though mixing chemicals (insecticides, fungicides, etc) or addition of adjuvants can have unexpected phototoxic results.  Consider a rotation that includes Conserve (spinosad; label indicates potential spotting on African violets), Avid (abamectin; label indicates potential phytotoxicity on Adiantum ferns and Shasta daisy), Flagship (thiamethoxam), and/or bifenthrin.  Complete list of chemicals can be found here.

Cottony Maple Scale egg hatch

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I already reported on cottony maple leaf scale crawlers which became

Cottony Maple Scale

Cottony Maple Scale ovisac on red maple twig. Photo: S.D. Frank

active a couple weeks ago. Now it is time for cottony maple scale.  The ovisacs of this scale occur on branches instead of leaves which is an easy way to tell them apart. Cottony maple scale seems to become most abundant on silver maple but I found this one on red maple. We do not have a lot of silver maple this far south. Control is similar to other soft scale recommendations found here.

Peak Japanese maple scale crawlers

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In Raleigh we have reached 900 degree days. This is around the time when Japanese maple scale drawer abundance will be peaking.  At least for the first generation. Unfortunately the crawlers have been emerging for a couple weeks and will continue for a couple more.  Thus, trying to target all the crawlers with a single insecticide application is tough.  However, some help can be provided with systemic neonicotinoids such as dinotefuran and translaminar insect growth regulators such as pyriproxifen. Good publications from University of Maryland and University of Tennessee have nice pictures and diagnostic characters. This has been an increasingly important pest so it is worth looking out for.