Northcentral Regional Aphid Suction Trap Network was turned on last week in at least eight states. As in 2005, Michigan has three trapping locations that cover a north-south transect:  MSU’s Saginaw Valley Bean and Beet Research Farm in Saginaw County; the MSU Entomology Farm in Ingham County; and the Kellogg Biological Station in Kalamazoo County.  By the end of June, we will set up two new locations: one at the MSU Extension office in Monroe County to cover southeast Michigan and another in western Michigan in Oceana County.  Monroe County has a high population of buckthorn, the overwintering host for soybean aphid; it experienced heavy, early aphid infestation in 2005, and thus may benefit from trapping information.  The location in Oceana County is specifically targeted to provide information to vegetable growers in Western Michigan, where soybean aphid is implicated in virus spread.

The traps suck in migrating insects, including winged aphids, flying over 20 feet above the ground.  The insects end up in a jar of antifreeze just above the fan in the base of the trap.  Sample bottles are changed weekly and mailed to the University of Illinois where aphids are removed, identified and counted.  The soybean aphid counts are posted on a web site, http://www.ncipmc.org/traps/, where you can view individual traps from each of the eight states. There are currently 33 traps on the network, plus 5 to 6 more that will come on line in June.

Later in the season, in late July and early August, increases in flight often time with peak infestations in soybean fields.  For example, last season (see the 2005 data at http://www.ncipmc.org/traps), tremendous numbers of soybean aphids were trapped in early to mid-August, when aphid populations peaked in nearby fields.  Such heavy aphid flights increase the risk of reinfestation in previously-sprayed fields we certainly experienced that frustrating situation in 2005.

In the last four years, heavy aphid flights in late July/early August coincided with virus infection in vegetable crops in Michigan. The suction traps can alert growers to a potential virus threat and may eventually help vegetable growers make decisions about late-plantings, for example, variety selection.

At the end of the season, the suction traps play their most important role, potentially predicting next year’s soybean aphid population.  Suction traps catch the winged males and females that leave soybean and go back to buckthorn, where soybean aphid overwinters.  In Illinois, the number of fall migrants caught in suction traps correctly predicted the next year’s aphid population (outbreak versus no outbreak) in four out of four seasons, including 2005. The 2005 season was the first year for the Regional network, across eight states. At the end of 2005, some areas (such as Michigan) had low fall trap catches; others (for example Minnesota) had high fall flights.  June 2006 is a critical test for the predictability of the traps in theory, Michigan should have low colonization this spring and Minnesota should have early, heavier colonization.  Stayed tuned!

And to follow up on the previous article about suction traps, here is the latest update on soybean aphid in soybean.  Dave Ragsdale from the University of Minnesota reports that soybean aphid was found in multiple locations throughout Minnesota on V1 soybeans. The earliest find was in mid-May on volunteer beans along the Minnesota River in south-central Minnesota. Soybean aphid was later found at the end of May in commercial soybean in northwest Minnesota (Dave says this is a good two to three weeks earlier than ever recorded in that part of the state.) and in a research plot south of the Twin Cities.

An updated fact sheet on where to get information about soybean rust forecasts, models and information can be found at: http://www.ipm.msu.edu/cat06field/pdf/6-8sbrinfo.pdf

Sentinel plot scouting in Michigan started this week. No rust has been reported. Soybean rust continues to move slowly down south. In Georgia plots were scouted for soybean rust, but none was observed on any of the samples. Most of their soybean sentinel plots are at the V5-V7 growth stage, with a few scattered plants at first bloom (R1). Weather continues to be hot and dry for most of the state with a few scattered thunderstorms. Previously infected sites that were destroyed are still not showing any new signs of infection. There have been positive finds of soybean rust on kudzu in north Florida. Although there hasn’t been any recent rain, high humidity has provided sufficient dew to allow sporulation and infection. All of the soybean sentinel plots are still negative. Some have started to bloom (R1).

Despite a report of “rust-like” spores caught in a spore trap at a Texas location, there was no soybean rust in a sentinel plot and three commercial fields in the area. There has been no rust observed on sentinel plots, commercial fields or kudzu patches. Sentinel plot scouting is underway in Louisiana. No soybean rust has been found.

Wheat streak mosaic virus was confirmed on the white wheat variety Caledonia at a research plot in Williamston, Michigan last week. A sample was sent to an outside lab that specializes in virus testing.

Symptoms show up as longitudinal yellow stripes on the foliage (see photo) and plants may be stunted. Other hosts include spring wheat, barley, corn, rye, oats and several annual and perennial grasses. This virus is vectored by the wheat curl mite, Aceria tulipae. Plants are frequently infected in fall, but symptoms don’t show up until spring.

Regional reports
1 -- Southeast
Ned Birkey

Weather
It has been highly variable with hot and cool temperatures this past week and locally heavy rain. We had some damaging hail last Saturday (June 3).

Corn is growing very rapidly, except where it is still struggling with wet soils and a lack of oxygen to the roots or a lack of nitrogen. Advanced fields are at the V8 stage, but fields with heavy clay soils or poor drainage have tremendous variations of height and color. Yellow corn may be tall or short and the result of nitrogen loss, a lack of nitrogen if sidedressing has not happened, or poor root growth. Although the hot Memorial Day weather dried out the soil at the surface, digging down, the soil is still very wet even four to six inches down. Some fields need cultivation with a rigid shank cultivator to loosen up the crust and aerate the soil to promote better root growth. These fields tend to be highly variable and even rolling shields are needed to protect the small plants. European corn borers are active at this time. I have not seen any significant insect feeding, though some European corn borer injury is present. Replant corn is emerging very quickly. Sidedressing continues, but is winding down. I have heard of more Roundup Ready corn being planted this year – not because farmers wanted that trait, but because they wanted an insecticide-treated corn, and it came as a stacked trait.

Soybean planting has not finished, and it will soon be two months since the first soybeans were planted in April. Most farmer attention has shifted to laying the corn before they worry about post-weed control sprays for soybeans.

Wheat is all headed and flowered. Fortunately, the hot weather over Memorial Day weekend did not terminate wheat development. It seems we often get some 90 degree weather in early June that does stop further wheat development. Depending upon the disease, resistance and flowering timing of a variety will depend upon how much disease we end up with. Not many fields were sprayed with a fungicide just prior to flowering.

2 -- Southwest
Bruce MacKellar

Weather
Thunderstorms Wednesday morning (June 7) left the region with fairly widespread rainfall totals of 0.75 inch or more. There was really no severe weather associated with this front, and for most folks, the rainfall probably would be considered beneficial. The eastern half of the region also had thunderstorm activity on Wednesday evening with stronger storms occurring in the coldwater area.

Commodity reports
Commercial corn has been growing rapidly ever since the hot weather over the Memorial Day weekend. Early planted corn in the region is approaching 13 inches in height (V7 to V8) and is growing rapidly. Quite a few folks have been very busy side dressing N on these fields. European corn borer moths have begun flying, and moth activity was on the increase on the warmer nights last weekend. The highest night count I have had on a black light in Van Buren County was in the lower 40s. A black light trap located on the Schoolcraft Prairie has had similar numbers last week with significant reductions in catches when the temperatures dip into the lower 50s. With high moth activity reported in the southeastern part of the state, it is likely that we will see egg laying, especially in the tallest corn fields, fairly soon. The best time to scout to determine if treatment is needed on non-Bt corn hybrids is when the larvae hatch. If you look for egg masses, look for the fish scale like whitish eggs laid on the undersides of corn leaves.

Seed corn planted just before the rains or delayed by the rains is beginning to come around fairly well. Watch fields for corn borer moth activity. There have been some reports of grass weed species coming through the pre-emergence herbicide treatments. You may also want to consider PSNT’s for fields that had nitrogen on “up front” in areas that received the highest rainfall totals.

A lot of the earliest planted soybeans are at V3 or V2 and are ready for post emergence weed control treatments. Insect feeding has been fairly light, although there has been some cutworm feeding on later planted fields in the area. The sentinel plots in this area are looking very clean at this point, and I have seen no soybean aphids.

The wheat in this part of the region is in the grain filling stage, and with cooler weather and moist conditions, we expect there to be less stress on the plants. Some fields were treated with fungicides, but the timing of flowering and the weather at that time probably will play the most significant role in determining if the sprays were warranted.

In general, the crop is looking fairly good.

In alfalfa, potato leafhoppers made their expected return over Memorial Day. Their numbers will be on the increase, so watch your re-growth alfalfa very carefully for the pest. The treatment threshold for 0- to 3-inch alfalfa is 0.2 leafhoppers per sweep, which is a pretty low number of insects. Harvest around rain showers is moving along, and the earliest harvested fields are approaching second cutting already.

3 -- West Central
Fred Springborn

Weather
Scattered rain showers on Tuesday night and Wednesday morning deposited 0.75 inches in many places and up to an 1.5 inches in areas of Newago County. We have quite adequate moisture.

Commodity reports
Growth stages in corn range from just planted to V6. Still some are thinking of replanting portions of fields.

Dry bean planting is underway.

Soybean planting is winding down. Advanced fields are V3.

Flowering is now complete in most wheat fields. Head scab symptoms have not been observed.

Oats are growing rapidly, flag leaves are fully emerged in most fields.

In alfalfa, harvest of first cut ranges from complete to just starting. Weevil damage is severe in some fields. Most producers are opting for cutting versus spraying at this point, hoping weather will allow for a speedy completion.

4 -- Central
Paul Gross

Weather
The past week has been a struggle for most farmers trying to finish planting. We seem to get scattered showers about every other day. In the northern part of the region, soils are saturated. As you go south, some areas have not received the rains others have gotten. There are many fields that will be replanted all or in part. Many growers are waiting for things to dry out to make those decisions.

Soybeans have their first and second trifoliate leaf. Many stands are spotty with some drown outs. Some fields will be replanted. Many growers are having little success getting herbicide applications on. Weeds are getting very large so check label recommendations for rates for these larger weeds.

The wheat crop is nearly done flowering. Many growers made fungicide applications to manage head scab. We are seeing some powdery mildew and septoria, but at this time, it is still low in the plant. There are a lot of small weeds in many fields that may cause harvest problems.

Alfalfa harvest has been a real challenge. There are a few growers that have been able to harvest while others are harvesting between rains. Getting hay dry has been nearly impossible. The alfalfa weevil is taking its toll on quality and yield. Scout regrowth to determine if an insecticide is needed. We have seen second cutting fields over threshold. The potato leafhoppers are also present in most fields at low levels.

Oats and barley are doing OK considering all the rain. The barley is very yellow, as this crop does not like wet soils.

Dry bean planting is beginning as field conditions allow.

5 -- Thumb
Mark Seamon

Weather
Seasonably warm weather through the past week has really helped to improve crop conditions. Some areas are still working on drying out from excessive rainfall.

Commodity reports
First cutting of alfalfa is pretty much wrapped up. New growth of earlier harvests looks good with good moisture and warm temperatures.

Many nice sugar beet fields have used the growing conditions to add a lot to top growth throughout the past week. Other challenged fields are looking better with more plant growth and a better idea of stand persistence.

The wheat crop is looking pretty nice with almost all fields completed flowering. The threat of head scab is real where rainfall and high moisture conditions were extended. Soil moisture conditions for grain fill are good and air temperatures have not been excessive, so yield should not be limited at this point of crop development.

Post emergent weed control in corn has been active on a huge number of acres. Weed control has been good in most cases with good growing conditions allowing for efficient herbicide action. Presidedress nitrate sampling continues to evaluate nitrogen credits before sidedressing.

A few soybean fields are being planted where rainfall has delayed planting. Recently planted fields are emerging quickly with good soil moisture and warm temperatures. Replant decisions should be made carefully after stand counts and referring to replant charts that list expected yield loss due to reduced stands compared to a delayed plating date. Populations in solid seeded soybeans need to be less than about 100,000 plants per acre (less than 80,000 in 30 inch rows) to expect a significant yield loss. While the delayed planting date may reduce yield more than loss of early planted stands.

A cool front will move from west to east across Michigan Thursday, bringing cooler and drier Canadian-origin air into the state and setting off a few isolated showers and thunderstorms in eastern sections of Lower Michigan. Behind the front, look for several days of fair, cool and dry weather. Temperatures during the next several days will fall back to below normal levels with mean temperatures generally remaining 4 to 8 degrees below the climatological norms. High temperatures will range from near 60 far north to the upper 60s to mid-70s south Friday through Monday. Low temperatures will range from the 30s north to the 40s south during the same time frame. Some patchy light frost will be possible in low-lying areas of interior northern Michigan Saturday and Sunday mornings. Slightly warmer temperatures are likely by early next week. The next chance for rainfall will come Tuesday or Wednesday of next week with a chance for scattered showers and thunderstorms across the state.

In the medium‑range, forecast guidance is suggesting split-stream jet stream flow across western North America joining into a strong, single west to east stream across the northern Great Plains and Great Lakes regions.

Both the 6-10 day and 8-14 day outlooks (covering June 13-17 and 15-21) call for below normal temperatures statewide. Precipitation totals during the 6-10 day time frame are forecast to range from near normal across southeastern sections of the state to below normal in the northwestern. A similar pattern is forecast during the 8-14 day period with totals expected to range from normal in northwestern sections of the state to above normal in the southeast. It is worth noting that forecaster confidence in these outlooks is considered lower than normal due to relatively large differences among the individual forecast tools and projections.

Earlier this year, meteorologists at Accu-Weather, a commercial meteorological firm in Pennsylvania, released an extended outlook that mentioned the possible return of “Dust-Bowl” type conditions to portions of the central United States. The Dust-Bowl era of the 1930s (especially 1934 and 1936) included some of the most severe heat and drought conditions experienced in the central United States during the last century. Many of the climatological records in Michigan for extreme maximum temperatures, including the state’s all-time high temperature of 112°F at Mio (July 13, 1936), were set in the 1930s.

The rationale for the outlook is associated with unusually warm sea surface temperatures over portions of the northwestern Atlantic Basin (The same warm waters that helped fuel a record number of tropical storms and hurricanes last summer and fall.) and relatively cool water in the eastern Pacific. These anomalous sea surface conditions were also thought to be in place during the 1930s and are thought to be associated with a westward shift of the low-level jet stream from just above the surface up to about 4,000 feet. The low-level jet stream is critical as to precipitation climatology across the Great Plains region as it acts to transport large quantities of Gulf of Mexico-origin moisture (the major “raw material” of precipitation) northwestward into the region.

Under the current scenario, the low-level jet stream would shift westward and flow more frequently over sections of arid Mexico (instead of the Gulf), reducing the amount of water transport into the United States and to less precipitation. There is another related issue referred to as an atmospheric “feedback” mechanism. When the earth’s surface is relatively well-watered (i.e. frequent precipitation), a significant amount of incoming solar energy goes into evaporating water. This can account for more than half of the total incident solar radiation. If there is less water to evaporate (i.e. low rainfall), a larger fraction of the incoming solar energy goes directly into heating the ground surface and the air above it, leading to relatively higher air temperatures. In addition, a portion of the water that falls as precipitation in the Great Plains is of local origin (The evaporation took place recently within a few hundred miles.), a phenomenon referred to as “precipitation recycling.” Therefore, prolonged drought can also reduce the amount of water available for future precipitation, which lends some scientific foundation to the old saying, “drought begets drought.”

Overall in this case, the forecasters believe that a reduction in regional precipitation over an extended period (months or years) will lead to a drier, warmer landscape. So does this mean that we will be looking at scenes from the Grapes of Wrath across sections of the central United States anytime soon? Only time will tell. Drought conditions as depicted by NOAA’s Palmer Drought Index are currently reported across large areas of the Rocky Mountain and Great Plains regions and current long lead outlooks do suggest warmer than normal temperatures across large sections of the southern United States (The NOAA long lead forecasters take the dry soil feedback mechanism into account as well.).

One thing is certain. The extreme conditions of the 1930s did not materialize overnight. Many months and even years of anomalous weather were involved, and some of the conditions were associated with poor land management practices that do not exist (or are not allowed) today. It is also worth remembering a helpful old rule-of-thumb adage that I picked up as an undergraduate meteorology student: Never forecast a new record. There is truth to this adage as climatological records represent the most extreme events observed, which means their probability of occurring is extremely small. Hopefully, that will remain true in this case as well.