Aug 7, 2016 - Potato Insect Pest Report #4 (July 14 – 25)
Dr. Vikram Bisht,
Plant Pathologist, Potato & Horticultural Crops,
Manitoba Agriculture
The aphid counts remained low in the 3rd week (July 5-11) and the the 4th week (July 12-18) especially in the southern seed production area. Potato aphids but not Green Peach aphids (GPAs) were found in these weeks. There were no aster leafhoppers (ALH) and potato leafhoppers (PLH) noted in the traps.
In the 5th week (July 19-25) the aphid counts have increased significantly over the previous week. Green peach aphids were trapped from the Portage area only. The potato aphids were trapped in all the three seed production areas. Potato aphids are fairly efficient PVY transmitters, but not as efficient as GPAs. The “other aphids” in the traps are poor transmitters, but make up with higher numbers.
With other crops in the region maturing and near harvest, the aphids will find the green potato crop very attractive. It may be helpful to the seed growers to consider tank mixing insecticide with the aphid-oils application, especially if the crop planted had some level of PVY in the seed itself.
Below are the results from suction and pan traps in seed fields for the 3rd, 4th and the 5th week.
Weekly Aphid Report – July 05 - July 11 (Week 3)
| Field # | Town | RM | Green Peach Aphid | Potato Aphid | Other Aphids | Total * | ALH | PLH | Comments |
|---|---|---|---|---|---|---|---|---|---|
| Southern Region | |||||||||
| Field 1, 34-1 | Reinland | Stanley | 0 | 1 | 0 | 1 | |||
| Field 2, 30-2 | Chortitz | Stanley | 0 | 1 | 0 | 1 | |||
| Field 3, 35-1 | Altona | Rhineland | 0 | 0 | 1 | 1 | |||
| Central Region | |||||||||
| Field 4, 25-7 | Holland | Victoria | 0 | 1 | 8 | 9 | |||
| Field 5, 26-3 | Glenora | Argyle | 0 | 0 | 3 | 3 | |||
| Field 6, 21-31 | McDonald | Portage La Prairie | 0 | 1 | 5 | 8 | |||
| Western Region | |||||||||
| Field 7, 19-12 | Wellwood | North Cypress | 0 | 5 | 8 | 13 | |||
| Field 8, 33-11 | Brookdale | North Cypress | 0 | 2 | 3 | 5 | |||
* The aphid counts are a summation from a suction trap and 2 pan traps in a field.
Weekly Aphid Report – July 12 - July 18 (Week 4)
| Field # | Town | RM | Green Peach Aphid | Potato Aphid | Other Aphids | Total * | ALH | PLH | Comments |
|---|---|---|---|---|---|---|---|---|---|
| Southern Region | |||||||||
| Field 1, 34-1 | Reinland | Stanley | 0 | 4 | 5 | 9 | |||
| Field 2, 30-2 | Chortitz | Stanley | 0 | 0 | 2 | 2 | |||
| Field 3, 35-1 | Altona | Rhineland | 0 | 0 | 0 | 0 | |||
| Central Region | |||||||||
| Field 4, 25-7 | Holland | Victoria | 0 | 1 | 3 | 4 | |||
| Field 5, 26-3 | Glenora | Argyle | 0 | 3 | 6 | 9 | |||
| Field 6, 21-31 | McDonald | Portage La Prairie | 0 | 1 | 1 | 2 | |||
| Western Region | |||||||||
| Field 7, 19-12 | Wellwood | North Cypress | 0 | 1 | 4 | 5 | |||
| Field 8, 33-11 | Brookdale | North Cypress | 0 | 3 | 2 | 5 | |||
Weekly Aphid Report – July 19 - July 25 (Week 5)
| Field # | Town | RM | Green Peach Aphid | Potato Aphid | Other Aphids | Total * | ALH | PLH | Comments |
|---|---|---|---|---|---|---|---|---|---|
| Southern Region | |||||||||
| Field 1, 34-1 | Reinland | Stanley | 0 | 3 | 3 | 6 | |||
| Field 2, 30-2 | Chortitz | Stanley | 0 | 2 | 4 | 6 | |||
| Field 3, 35-1 | Altona | Rhineland | Sample not available | ||||||
| Central Region | |||||||||
| Field 4, 25-7 | Holland | Victoria | 0 | 3 | 26 | 29 | |||
| Field 5, 26-3 | Glenora | Argyle | 0 | 2 | 5 | 7 | 11 | ||
| Field 6, 21-31 | McDonald | Portage La Prairie | 2 | 0 | 2 | 4 | 9 | ||
| Western Region | |||||||||
| Field 7, 19-12 | Wellwood | North Cypress | 0 | 8 | 17 | 25 | 2 | ||
| Field 8, 33-11 | Brookdale | North Cypress | 0 | 4 | 7 | 11 | 1 | ||
Currently, there is no report of any serious Colorado potato beetle (CPB) feeding in commercial potatoes.
European Corn Borer:
Delta trap monitoring for the ECB moths using pheromone lures continue to show some adult moth activity – in Carberry, Brookdale in Rural Municipality of North Cypress-Langford, Treherne (RM of Victoria), Shilo (RM Cornwallis), Glenboro (RM of Glenboro-South Cypress) and Carman (RM of Dufferin) area.
After a peak activity in mid-July, the number of trapping has reduced. After the appearance of very young larvae (Figure 1) was the trigger for insecticide application in fields close to last year’s serious infestations. Some ECB injury and larvae were noticed in the Carberry area.
Insecticide application could be considered when significant larval counts appear, and especially in areas where the stem infestation was high in 2015. Please consult the 2016 Manitoba Guide to Field Crop Protection for the choice of insecticides.