MSU Urban IPM Alerts

Fall - we associate this time of year with an array of vibrant colors on our deciduous trees. However, the yellowing of evergreen trees might cause some concern. Every fall, the inner needles of evergreens start to turn yellow and are dropped over time. This is a natural process known as seasonal needle drop. Please see more information in the attached alert document.

Sincerely,

Eva Grimme

Grasshoppers continue to be an issue for yards and gardens for several areas in Montana, which will last into the fall. Management is very challenging, though some options are available. Consider focusing on the most vulnerable trees and plants for management (and those of importance). See the alert for more information.

After an early cold snap this past September in addition to a tough winter, seeing signs of stress and chlorosis in trees is prevalent in Montana landscapes this summer. Stress in trees can appear as premature fall coloration, branch/crown dieback, curling/wilting of leaves, etc. Chlorosis is a change in leaf coloration (yellowing, early fall coloration, dark green veins, eventual browning of leaf edges, etc.) that is often brought about by a nutrient deficiency. The most common nutrient deficiency in Montana landscapes is due to insufficient iron or nitrogen uptake. Stress and chlorosis can often compound on each other, further impacting tree vigor.

Please contact Abi Saeed (406-994-6523 or abiya.saeed@montana.edu) for questions and recommendations.

If you are seeing brown spots or galls on the leaves of your apple, crabapple, or pear tree, these spots are likely galls formed by blister mites. See the attached alert for more information.

The Schutter Lab is receiving many samples and questions about herbicide symptoms occurring in home gardens. In most of these cases we suspect carryover of persistent herbicides in recently purchased or recently applied topsoil, compost, or manure. The attached document is an update to the Urban Alert we sent about this topic in June 2020, and it includes recommendations about whether or not it is safe to consume vegetables showing herbicide injury symptoms. 

We have several social wasps in Montana. Except for the Western yellowjacket, social wasps are typically not aggressive unless their nest is disturbed. Most are beneficial and feed on a lot of garden pests. If you have had issues with Western yellowjackets in the past and want to keep them away this year, it is time to put the traps out. Queens become active around late May, searching for nesting sites. 

Montana has several home-invading weevils that come into our homes starting in April and
through November. They are harmless to humans and structures.

There has been a lot of press about the Asian giant hornet, Vespa mandarinia, aka the murder hornet. It is not known to be in Montana at this time. Two sightings have been confirmed in Whatcom County, Washington in Dec 2019 and in British Columbia in the fall of 2019. See this fact sheet/alert from Alyssa Piccolomini from the Montana Department of Agriculture.

The common ticks in Montana this time of the year are the Rocky Mountain wood tick,
Dermacentor andersoni, and the American dog tick, Dermacentor variabilis. The two species look very similar. We don’t have either of the two species of black-legged ticks (formerly deer ticks) that vector Lyme disease in Montana.

MSU Extension has just released three timely MontGuides to help gardeners, both new and experienced, to extend their vegetable growing season, plan, plant, and maintain vegetable gardens, and then save seeds for next year’s garden.

For those looking for a home project to help extend their growing season for early planting, Hotbeds, Cold Frames, and Low Tunnels for Montana Gardeners - MT199803AG explains how this can be done. With this revision of the previous MontGuide, low tunnel construction has been added.

Download Now: Hotbeds and Cold Frames for Montana Gardeners

The all-new Successful Home Vegetable Gardening in Montana has been expanded. In addition to sections on planting, planning, and maintaining gardens, sections on disease and insect pest management have been added.

Download Now: Successful Home Vegetable Gardening

For those gardeners who would like to save their own seeds for next year’s garden, Harvesting and Saving Garden Seeds has been updated. Many seed companies had to stop selling vegetable seeds to home gardeners this year and only supplied professional growers. Saving your own seeds can help in food security, and also tailoring your garden to your specific conditions.

Download Now: Harvesting and Saving Garden Seeds

For additional information please contact Cheryl Moore-Gough at cheryl@montana.edu.