When does the canola become more resistant to flea beetles?
Estimating % defoliation. Estimating % defoliation can be tricky, as our eyes are drawn to the damage and it is easy to overestimate how much feeding has occurred. Having a photo key as a guide can be useful for learning to assess defoliation levels.
Cutworm Feeding. High levels of feeding by cutworms has been noted in sunflowers in the Carman and Sanford areas, and in corn in the Starbuck area.
Insecticide application tips for cutworms.
Insect Monitoring Programs:
Diamondback moth: Diamondback moth counts have increased in some locations in eastern Manitoba and the Swan River Valley.
Bertha armyworm: The map provided in the report indicates at what stage the pupae of the bertha armyworm are in their development. Currently, some may have accumulated enough heat to be about 60-75% through their pupal development.
Submitted by: John Gavloski, Entomologist & Vikram Bisht, Field Crops Pathologist, MAFRD
Insect and disease activity continues to be low on crops in Manitoba.
The cool temperature has slowed the emergence of many insects.
There is no evidence to date of any major movement of insects that get blown into Manitoba form the southern U.S., such as diamondback moth and aster leafhopper.
The update provides information on the following topics:
Grasshoppers: When will emergence likely start? Degree day models can be used to forecast anticipated dates of emergence for these pest species. Based on such models it will likely be early-June before we see a start to the emergence of these species of grasshoppers in most areas.
Recent Rain and Grasshoppers? The recent rains will likely do very little to negatively impact the survival of our pest species of grasshoppers.
Insect Monitoring Programs. Updates on diamondback moth, wireworms & cutworms.
The purpose of the updates is to compile information on insects and diseases of current concern to those growing or monitoring crops in Manitoba, and present a summarized weekly report that can alert farmers and agronomists to concerns in their region. This relies on insect and disease observations and concerns being reported by those monitoring crops. So the cooperation of agronomists and farmers in providing information for these reports is greatly appreciated. Results of insect and disease monitoring programs will also be presented in these reports.
Agronomists, Farmers, Farm Production Advisors, and others scouting crops: Please remember to send in reports of insects or plant diseases over the growing season so we can make these updates as complete as possible, and alert farmers and agronomists where and to what degree insects and pathogens are of concern or being controlled.