Aphid Alert Seasonal Summary

Greetings!

Welcome to the last issue of Aphid Alert for 2017. The harvest has started and most of the vines have been killed.  The 2017 season was marked by heavy vector pressure; we had high populations of efficient vector species and they were widely dispersed across the region.  This means we had very high risk of PVY transmission.  The actual amount of disease that was actually transmitted, however, will depend on how much inoculum was present in each area.

The 2017 wrap up data is posted at the bottom of the page with maps of both 2017 & 2016 PVY Vector Risk Index values.  In addition, we've posted a chart of the actual total number of aphids collected by species for each location.

The high number of aphids probably resulted from several factors.  A mild winter would have meant high survival of several aphid species that overwinter in MN & ND.  The presence of Green Peach Aphid and other species that don't overwinter in the region means we had Low Level Jet stream winds bringing the aphids up from their southern overwintering areas. 


Dr, Min Zhu, when she was a PhD candidate in MN back in 2004, established that many of these vector species are re-established annually from aphid populations in states west of the Mississippi River (including Arkansas, eastern Colorado, Kansas, Louisiana, Missouri, Oklahoma and northern Texas).  Her work showed that winged aphids from these locations are brought northwards on Low Level Jet (LLJ) wind events.  These wind events are (part of the Jet Stream that goes up the center of the continent) are low enough that insects travelling in them won't freeze and they're fast enough to get them up from Texas within 24-48 hours (longer and the insects would dessicate).  They're an insect interstate travel route, they transport insects up from the south and deposit them in our region when rain events basically 'dump' them from the sky (bringing a very different meaning to being 'rained out').  Think of LLJs as Aphid Airlines...

Past LLJs can be evaluated using one of NOAA's online tools called HYSPLIT (on the web at: http://ready.arl.noaa.gov/HYSPLIT.php).  It uses archvied weather data to determine where LLJs occurred, how long they lasted and what altitudes (NOAA is one of the best record keepers in the world).  We used HYSPLIT to 'back track' wind events that hit the Aphid Alert trapping regions early May to mid-June 2017.  We found multiple LLJs that coincided with rain events in our region.  This means there were lots of opportunities for successful aphid movement from the south.

For example, below is a map showing of a Low Level Jet wind that arrived over Grand Forks on June 10. This event originated in central Oklahoma (well within the area where Green Peach aphids overwinter) and occurred at 1500m Above Ground Level, an excellent altitude for wind to transport aphids that distance.  On June 10th, Grand Forks received 0.2" of rain which could potentially have dumped out anything travelling on that wind event.  That doesn't mean there were any aphid on that particular flight of Aphid Airlines, but it is a possibility.        

There were several LLJs this year that could have impacted many of the areas in our trapping region, which potentially explains the number and wide distribution of Green Peach Aphid this season. 

Low Level Jet Arriving In Grand Forks June 10, 2017

2017 Wrap-Up Data

Cumulative PVY Vector Risk Index for the Season of 2017

Cumulative PVY Vector Risk Index for the Season of 2016

2017 Cumulative Total Aphid Species Capture by Trap Location

Trap Catches Identified to September 15

Greetings!

Welcome to the Aphid Alert update for the week ending September 15. We are winding down the season with only 4 sites reporting and only 13 total vector aphids captured. Most sites have closed down and I expect that next week will be our seasonal summary.

Although few aphids were captured this week, 2 sites reported Green Peach Aphids (2 from Brooks MN and 1 from Tappen ND). Otherwise only several other vector species were recovered from the traps.

While there was very little additional Vector pressure added this week, the season's cumulative PVY Vector Risk was very high for the 2017 season.

Scouting for aphids in potatoes:

·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on Any Image for Full Sized Version

Total 2016 PVY Vector Risk Index for Comparison

Weekly Trap Capture by Location

Cumulative Seasonal Capture & PVY Vector Risk Index by Location

Trap Catches Identified to September 08

Greetings!

Welcome to the Aphid Alert update for the week ending September 08.  The colder weather has brought along at least one good thing, the aphid vector numbers took a real tumble this week. 

With only 6 sites reporting this week, only 34 vector aphids were recovered from across the area (that number was 244 last week!) Only one site had vector numbers in the double digits; Humboldt reported 12 vector species (compared to 93 last week).  No Green Peach Aphids were recovered in the past week and Soybean Aphid numbers likewise were much lower.  

Many locations have already vine killed. This would be a good year for early vine kill; if fields haven't yet been killed, this would be a good time to think about it 

Remember, keep scouting!

Scouting for aphids in potatoes:
·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on Any Image for Full Sized Version

Total 2016 PVY Vector Risk Index for Comparison

Weekly Trap Capture by Location

Cumulative Seasonal Capture & PVY Vector Risk Index by Location

Trap Catches Identified to September 01

Greetings!

Welcome to the Aphid Alert update for the week ending September 01.  Trap catches took a further drop this week but several trap locations are still reporting numbers well above last year's.  The number of locations reporting is starting to decrease as well, with only 8 locations sending in samples this week.  

Only two Green Peach Aphids (GPA) were recovered this week, 1 from Gully MN and the other from McVille ND.  Ada led this week's trap catch with 75 vectors, followed by Perham with 22, Gully with and 20 and Lake of the Woods with 15.  Al other reporting locations had trap catches in the single digits.  PVY Vector Risk Index values are slowing but very high for the whole season. 

As mentioned last week, most PVY transmission in this region occurs in the later part of the season.  Aphid flights are decreasing but still much higher than flights at this time last year!  This would be a good year for early vine kill; if fields haven't yet been killed, this would be a good time to think about it.  

Remember, keep scouting!

Scouting for aphids in potatoes:
·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on Any Image for Full Sized Version

Total 2016 PVY Vector Risk Index for Comparison

Weekly Trap Capture by Location

Cumulative Seasonal Capture & PVY Vector Risk Index by Location

Trap Catches Identified to August 25

Greetings!

Welcome to the Aphid Alert update for the week ending August 25.  Trap catches took a drop this week but numbers are still relatively high compared to last several years.  The average catch per trap last week was approx 67 vectors per trap location, although that was heavily influenced by two locations with over 500 aphids between them.  Even dropping those two traps out of the calculations, the remaining traps still averaged 33 vectors per location.  Traps this week averaged just 21 vectors per location.  The total trap catch for 2016, however, averaged only 29 per location for the entire cumulative season!  

The number of Green Peach Aphids (GPA) were down this week but 7 sites still captured a total of 9 GPA.  Soybean aphid numbers were also down this week but both Bird Cherry Oat and Corn Leaf Aphids, coming out of small grains, were still relatively numerous. 

Given the number of PVY vectors still present and flying across the entire region, it's important to remember that most of our PVY transmission occurs in the later part of the season.  Aphids leaving other host crops as they decline move to crops that are still green.  This would be a good year for early vine kill; if fields haven't yet been killed, this would be a good time to think about it.  

Remember, keep scouting!

Scouting for aphids in potatoes:
·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on Any Image for Full Sized Version

Total 2016 PVY Vector Risk Index for Comparison

Weekly Trap Capture by Location

Cumulative Seasonal Capture & PVY Vector Risk Index by Location

Trap Catches Identified to August 18

Greetings!

Welcome to the Aphid Alert update for the week ending August 18.  The number of vector captured in traps dropped slightly this week compared to last (901 total vectors captured last week and 853 this week).  These numbers, however, still are very high and the PVY Vector Risk Index continues to rise steeply with weekly jumps far larger than total Index values from last year.  The PVY Risk Index maps tells the story pretty clearly, we're having a very heavy aphid year with high populations in most areas.  We strongly recommend scouting and the use of crop oils.  Anti-feeding insecticides should be applied if required (see below) 

Trap catches at two locations were still in the hundreds this week (Humboldt with 337 vectors and Ada with 209).  Green peach aphid is still being recovered from numerous locations, some in high numbers.  Soybean aphid flights continue in several locations with ND now seeing movement of these aphids.  Corn leaf aphids remain numerous and Bird Cherry Oat aphids are also starting to rise.  Sunflower aphids took a rise in several of the northern locations and Buckthorn aphid flights are rising as well.  Hopefully the increased movement of both Soybean aphids and Buckthorn aphids will soon represent movement back to the overwintering host of both of these species, Buckthorn.

The PVY Risk Index map, weekly counts and cumulative PVY Index values are attached below.  Be advised of the increases in your area.

Remember, keep scouting!

Scouting for aphids in potatoes:
·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on Any Image for Full Sized Version

Total 2016 PVY Vector Risk Index for Comparison

Weekly Trap Capture by Location

Cumulative Seasonal Capture & PVY Vector Risk Index by Location

Trap Catches Identified to August 11

Greetings!

Welcome to the Aphid Alert update for the week ending August 11.  This continues to develop into a very high aphid year.  Trap catches continue to be high and the PVY Vector Risk Index continues to rise.  We strongly recommend scouting and the use of crop oils.  Anti-feeding insecticides should be applied if required (see below) 

Trap catch was very high in several locations, with three sites topping 3 figures in vector counts (Ada at 217, Brooks at 173, and Humboldt at 205).  Green peach aphid (the most efficient vector of PVY) continues to be numerous this year with 28 being captured in the past week (12 from Humboldt).  The numbers of this vector are not only high but widespread across the region with few sites reporting no presence in trap catches. 

Cereal aphids are starting to move out of grains and are being recorded in traps at high number, especially prevalent this season are corn leaf aphids which are to this point are the most common vector species recovered from traps this year.  This week is no exception with many sites recovering relatively high numbers (e.g. 64 of which were recovered from the Ada location, 40 from Humboldt, and 56 from Brooks).  

Also numerous this week were soybean aphids, a startling 128 of which were recovered from the Humboldt trap location, indicating a major flight.  The current outbreak of soybean aphids in the Red River Valley of MN & ND poses a particular risk to seed potatoes.  These aphids will not colonize potatoes but in high population years will readily enter fields, probing to test if plants are suitable hosts.  Because potatoes aren't hosts for this species, they do not initiate feeding but move onto the next plant.  In so doing they will acquire and transmit any inoculum in the field.  This is problematic as they enter in high numbers, passing through the fields until reaching soybeans.

Given the high vector catch numbers, and the potential for more, the use of crop oils is strongly recommended.  Data shows that narrow range mineral oils (e.g. Aphoil, Stylet Oil) applied at least once per week can significantly decrease the spread of PVY (twice per week is even better).

Remember, keep scouting!

Scouting for aphids in potatoes:
·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on Any Image for Full Sized Version

Total 2016 PVY Vector Risk Index for Comparison

Weekly Trap Capture by Location

Cumulative Seasonal Capture & PVY Vector Risk Index by Location

Trap Catches Identified to Aug 04

Greetings!

Sorry last week's report is late, we've had some technical difficulties!  This is officially a high aphid year!  With the increasing numbers of vectors, we strongly recommend scouting and the use of crop oils.  Anti-feeding insecticides should be applied if required (see below).

We continue to see high aphid numbers as well as an increasing PVY risk index. Sites that had high vector numbers include: Ada (282), Brooks (164), Crookston (99), Gully (116), Hoople (199), Humboldt (108), Lake of the Woods (86), McVille (145), Sabin (176), Staples (149) and Verndale (159). Meaning that in 11 of 16 traps reporting this week, we had high numbers.

Green peach aphid was found in 5 locations as well, including: Gully (1), Humboldt (3), Lake of the Woods (2), Sabin (2) and Verndale (1).  Small grains are maturing so we're also seeing an increase in small grain aphids (Ada had 219 Corn Leaf Aphids in their trap this week).  Soybean aphid numbers remain up, with the current outbreak of soybean aphid in MN & ND, we can expect large numbers of these insects to be moving into seed potato fields.

Remember, keep scouting!

Scouting for aphids in potatoes:
·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on any figure to see full size version.

Total 2016 PVY Risk Index for Comparison

Weekly Trap Capture by Location

Cumulative PVY Risk To date by Location

Trap Catches Identified to July 28

Greetings!

Welcome to the Aphid Alert update for the week ending July 28.  The aphid year continues - with a vengeance!

Trap catch did vary slightly this week; some reporting record numbers while others not so much. The PVY risk index skyrocketed in some sites due to high vector capture. Vector numbers were up at Brooks (81), Gully (35), Moran (25), McVille (84), Hoople (92), Staples (39) and this weeks big one - Humboldt with 183 vectors.  A few Green Peach aphids were present as well in Staples (4), Humboldt (3), Gully (2) and Hoople (1).

This year continues to be a high vector year. Soybean aphids are still on the rise in some soybean fields throughout much of MN.  Some of these populations continue to show pyrethroid resistance. Meaning that some fields still aren't quite getting adequate control. This may add to the number of soybean aphids moving into seed potato production areas.  While soybean aphid does not colonize potatoes, it is indeed a vector. So remember to keep your eyes open. We have started to test for soybean aphid resistance in some NW MN fields. We are looking for samples from sites that are reporting levels of resistance. That way we will have a better idea of both where we are seeing this resistance as well as what the actual level of resistance is.

Scouting obviously should be on the To Do list by now.  Due to another week of  high vector catch numbers, crop oils are still highly recommended. Data shows that narrow range mineral oils (e.g. Aphoil, Stylet Oil) applied at least once per week can significantly decrease the spread of PVY (twice per week is even better).

Remember, keep scouting!

Scouting for aphids in potatoes:
·         Select leaves from the lower to mid canopy.
·         Lower, older leaves will have more established colonies and aphids prefer the balance of nutrients found here; aphids are rarely found on leaves in the upper canopy.
·         Avoid leaves on the ground or in contact with the soil.
·         In seed potatoes there is only a threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides an effective control for PVY.
·         The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to field colonization by aphids may reduce the transmission of PVY within fields. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY.
·         In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.

The PVY Risk Index Index  Not all species of aphid are equally efficient at transmitting PVY, some are better than others (green peach being the most efficient vector of PVY).  So, the total number of aphids in a trap don't necessarily reflect just how much vector pressure there is at that location. The PVY Vector Risk Index compares aphid numbers, incorporating their relative vector efficiency compared to the Queen of PVY vectors (green peach aphid!).  Using averaged reference comparisons from the literature, we multiply the number of each aphid species captured by its efficiency compared to Green Peach Aphid to more accurately depict risk posed by the species being trapped.  We then sum the totals.  The PVY-VRI values are presented on the tables below but also on maps comparing current cumulative risk to the total risk from the sample sites of last year (to compare with your local winter grow out results).

Click on any figure to see full-size version.

2016 PVY Vector Risk Total for Comparison

Weekly Catch by Location

Cumulative Species Catch to Date by Location