Common garden troubles this June:
Garden Week Twelve 6/26/2018
Common garden troubles this June:
The weather has warmed, the gardens are growing and so are the pests. According to the Pacific Northwest Pest Alert Network, the first summer pests and diseases are Potato Psyllid, Scale on Honeylocust, Spider Mites, and Powdery Mildew. Let’s take a closer look at Potato Psyllid and Spider mites this week.
Bactericera cockerelli, commonly referred to as the Tomato Psyllid or Potato Psyllid, this species can affect other members of the solanaceous family, including potatoes, tomatoes, peppers, eggplant, and other nightshade plants. First identified as a potentially invasive pest in the early 1900’s, it became a serious problem by the 1920-1930’s. The small winged pest lays individual yellow eggs along the edge and mostly on the underside of leaves. Pale green upon emergence, they begin turning dark grey to brown within 2-3 days, eventually becoming grey or black. Identifying features include: White markings on the head, thorax, first and last segments of the abdomen. Often confused with the nymphs of whiteflies, they remain sedentary, while whiteflies will move if disturbed. Diseases associated with this pest are Pysllid Yellow and Zebra Chip. It is believed a toxin associated within this insect may cause ‘psyllid yellow’ found both in potatoes and tomatoes. Pysllid Yellow presents as a yellowing of the plant, disrupts plant growth and damages fruit size. Zebra Chip presents with discolored and curled leaves. When fried, potatoes present with blotches, stripes or streaks. While the appearance may not be acceptable in the potato chips, I have found no information regarding the health risks to humans.
Spider Mites, a member of the arachnid family, bruise the cells of plants when feeding, causing lightening or bleaching spots where the cells have been damaged. Seen through a magnifying glass, spider mites come in various colors and produce masses of webbing. Plants which are not watered well provide more nutrients to the spider mite. Taking care of your plants will help them to stave off an infestation. Note that the use of pesticides will kill the spider mites’ predators, which include, the lady beetles (aka “spider mite destroyers”), trips, predatory mites, minute pirate bugs, and big-eyed bugs. Other than biological controls, it is best to cut and remove invested branches and leaves, as spider mites are resistant to chemical treatments. For more information on identifying and managing these pests, check out: http://extension.colostate.edu/topic-areas/insects/spider-mites-5-507/
Maybe next time we will take a closer look at Powdery Mildew or Scale on Honeylocust. In the mean time you can learn more at:
http://pnwpestalert.net/alerts/crops/
https://pnwhandbooks.org/plantdisease/host-disease/sugar-beet-beta-vulgaris-powdery-mildew
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7410.html
