Trap Catches to Aug 12, 2022.
Another large jump in aphid numbers this week with an accompanying rise in the PVY Vector Risk. The increase through August so far for this year's regional aphid population seems to mirror the average population growth from 2013 through 2020. In other words, weekly captures are still increasing. The total numbers of PVY vectors are still only half what they were at this point last year, but if the weekly increase in numbers continues, our total counts could be close to 2021. The graphs below show the average regional weekly capture in 2021, the average regional weekly trap captures for this year, and the seasonal regional captures by week averaged from 2013 through 2020. Note that in 2021 (upper left graph), by August, weekly captures had peaked and were decreasing, this year (upper right graph), half way through August and our weekly captures are still increasing. The 8 year average pattern of weekly captures (bottom of the 3 graphs) indicates our typical peak occurs in August.
Soybean Aphid numbers continue to increase, as do our cereal aphid numbers with Corn Leaf and English Grain aphid numbers taking a bit of a jump. Buckthorn Aphids were recovered from numerous trapping sites as were thistle aphids.
Another single Green Peach Aphid was recovered from the trap in Becker, MN and there have been potential recoveries in Manitoba as well. This indicates that there may have been at least a couple of immigration events this season. Green Peach Aphids do not overwinter this far north, and their populations are re-established from the south only by very specific low-level jet wind events. Looks like this has happened in at least two locations this year.
In any case, numbers are rising, vector species are present.
So... Keep scouting, and we'll keep counting...
Cumulative Aphid Species Capture and PVY Vector Risk Index to Aug 12, 2022
