Trap Catches to Aug 11 - Aug 18, 2023.
With 14 trap locations reporting this week, catches were down from last week (780 vector aphids this week, down from 891 last week). However, due to the species captured, the increase in PVY Vector Risk Index was greater than that of last week (115.9 this week compared to 106.7 last week). Much of this was due to greater numbers of green peach aphids being captured this week (23 this week compared to only 4 last week). We are in a high vector risk year, far exceeding that of last year at this point. In 2022, however, most of our vector capture came in the last two weeks of August. Hopefully we won't continue that pattern. Our current pattern of trap catches does fit the pattern of the 2013-2020 average trap capture but is much higher (note the y-axis scale on the 2 graphs below).
A total of 780 vector aphids were recovered in traps from August 11-14. These included a rise in green peach aphid, the most efficient vector of PVY. Green peach aphids were recovered from 6 locations, several of which were the same locations this vector was captured last week. Soybean aphid captures were higher than last week, and, as with last week, were collected at all traps locations. English grain aphids were recovered from all but one trap location and numbers were basically the same as last week (1 less...). Potato, thistle, cotton/melon, and buckthorn aphids were all numerous and collected at most locations. Many of these, especially green peach aphids, are very effective vectors of PVY, and their presence in high numbers skewed the PVY Vector Risk Index to be higher than last week's even though 110 more vector aphids were captured last week.
As mentioned, last year's population mostly came on late in the summer, however, we've already exceeded both the cumulative number of vector aphids captured last summer. Our PVY Vector Risk Index is also higher than last year's total. The 2013-2020 averages do indicate late season increases are possible. Hopefully the weather will cool, especially the night lows, and the populations will start to decrease. But given the current situation, vector management is probably a good idea...
So, you keep scouting and we'll keep counting.
Scouting for aphids in potatoes: