NYS IPM  Weekly Field Crops Pest Report, July 27, 2018

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View from the Field

Western Bean Cutworm (Richia albicosta)  

We have a Western bean cutworm moth pheromone-trapping network that monitors this pest across the state. Western bean cutworm moth captures increased dramatically this week. We had 4101 moths caught this week as compared to 332 last week across the state. Start scouting your pre-tassel corn for egg mass and small larvae. There have been reports of Western bean cutworm over threshold and will need to be sprayed. For more information see below.

Photo by Mike Hunter-1st instar western bean cutworm larvae

Potato Leafhopper (Empoasca fabae)

There are still reports of potato leafhopper over threshold in fields across the state. Many of the fields have nymphs, which do more damage than the adults do. I was in a new seeding that was above threshold for potato leafhopper this week. About 90% of the plants showed potato leafhopper burn. Once the plant has leafhopper, burn there is a dramatic loss in quality and yield.

Potato leafhopper “burn” damage

Article on how to scout for potato leafhopper in alfalfa: http://blogs.cornell.edu/ipmwpr/time-to-scout-for-potato-leafhopper-in-alfalfa/

Soybean Aphids (Aphis glycines)

Jeff Miller (CCE Oneida County) reports finding soybean aphids on soybeans over threshold. Others have also reported increasing soybean aphid populations. Along with the increase of soybean aphids, lady beetles and other predators and parasitoids have increased keeping many fields under the economic threshold. The economic threshold is 250 aphids/plant between the R1 and R5 stage of soybean growth. See last week’s article on how to scout for soybean aphid. http://blogs.cornell.edu/ipmwpr/scouting-soybean-aphid/

Downy Mildew (Peronospora manshurica)  in Soybeans

There were reports of downy mildew on soybeans this week. Downy mildew is a common disease of soybeans and rarely causes yield losses. This disease proliferates under high humidity and cool temperatures. The fungus can overwinter on last season crop residue and can the transmitted by seed. Fungal spores are transmitted to the plant by wind and rain. When conditions are right the disease can spread quickly through a field. If the seed was infected with downy mildew the seeding will also be infected. Downy mildew is a biotrophic organism. This means that the disease can only grow and reproduce in associated with soybeans. The disease can have rapid genetic changes in response to the genetic changes to the soybean plant because of this close relationship. There are many different races of this disease and it is monitored closely when new cultivars are being bred.

Management:

  1. Use certified disease-free seed. If you use seed that is not certified are saved seed from your previous harvests many contain the pathogens we discussed earlier.
  2. Use resistant cultivars; ask your dealer how cultivars compare for disease susceptibility or resistance and productivity. Make sure the cultivar is suitable for your specific region of the state.
  3. Use a fungicide seed treatment at planting. This will kill pathogens that might infect the seed at planting. If you are organic make sure the soil temperature is over 500 This will allow the soybean to grow quickly and avoid pathogens in the soil.
  4. Plow infected residue under the soil surface. This will help reduce the amount of disease laying on the surface that can infect the next crop.
  5. Foliar fungicides are seldom warranted in New York

True Armyworm (Pseudaletia unipuncta)

There were more reports this week of True armyworm being found in cornfields across the state. Armyworm issues should end soon as the corn gets taller and armyworms pupate and will no longer feed.

 

Weather Outlook – July 26, 2018

Jessica Spaccio

NOAA Northeast Regional Climate Center, Cornell University

Last week temperatures were near-normal to 4 degrees above-normal. Precipitation has ranged from less than ¼” to over 4”. Base 50 growing degree-days ranged from 90-170. Moderate drought and abnormally dry conditions expanded in northern NY.

Dryer, less humid conditions before unsettled weather returns.

Today will be mostly dry after a long stretch of wet weather exits the state; temperatures will be in the mid 70s to mid 80s with lower humidity. Western NY will have afternoon showers and thunderstorms ahead of a cold front, with the possibility for severe weather (damaging winds and locally heavy rain).  Overnight lows will be in the low to mid 60s.

Friday highs will be in the 70s and 80s with scattered showers and thunderstorms due to a frontal passage; there is a slight chance for severe weather (damaging wind, small hail). Overnight temperatures will be in the mid 50s to low 60s.

Saturday temperatures will be in the 70s to mid 80s with scattered afternoon showers. Overnight temperatures will be in the mid 50s to low 60s.

Sunday highs will be in the mid 70s to mid 80s with mostly dry conditions. Overnight temperatures will be in the mid 50s to low 60s.

Monday temperatures will be in the 70s to low 80s with scattered showers and thunderstorms. Overnight temperatures will be in the 60s.

Tuesday highs will be in the 70s to low 80s with scattered showers and thunderstorms. Overnight temperatures will be in the 60s.

Wednesday possible scattered showers and thunderstorms with highs in the low 80s. Overnight temperatures will be in the 60s.

The seven-day precipitation amounts will range from half an inch to over two and a half inches.

The 8-14 day outlook (Aug 2-8) favors above-normal temperatures and above-normal precipitation for all of the state.

 Maps of 8-14 day outlooks

National Weather Service watch/warnings map

US Drought Monitor

CLIMOD2 (NRCC data interface)

Western Bean Cutworm Update 7.28.18

Western bean cutworm trap catches took this past week with 10X as many moths caught this week than last. Higher moth captures more often found in western and northern county than southern or eastern locations. See summary table below.

Monitoring fields for WBC egg masses:

As trap accumulations approach 100 moths per traps risk of WBC infestation increases and field monitoring for egg masses and young larvae is recommended. NOTE: Sometimes traps do not indicate what is in the field. You should scout all fields even with low trap captures.

Pre-tassel corn is the preferred host for egg laying WBC moths. Egg masses will be laid on the upper surface of leaves close to emerging tassels including leaves in the whorl. Check 10 – 20 consecutive plants in at least 5 random locations in the field. Threshold for field corn is 5% of plants with WBC egg masses. Egg masses are typically laid on upright leaves or those just beginning to lay over. I usually check top 4 leaves.

If leaves are oriented towards the sun you can see the egg masses better on the top side of leaf or if looking at the bottom surface of leaves look for a shadow of an egg mass on the upper surface of the leaf.  WBC eggs take ~5 – 7 days to hatch turning purple 1 – 2 days prior to hatch. Newly hatched larvae initially feed on their egg case and then make their way to silks or ears. If suitable food sources are not found the larvae will starve.

Several video’s are available on-line on how to monitor for WBC egg masses in corn. https://www.youtube.com/watch?v=cH-yVeDuUM0

http://extension.entm.purdue.edu/pestcrop/2014/issue15/index.html#video1

https://www.youtube.com/watch?v=gLeTgEo_jiQ

Pictures of WBC larvae and moths including look-a-like moths and larvae can be found at: http://www.msuent.com/assets/pdf/07WBCID.pdf

 

Clipboard Checklist

Keith Waldron, NYS IPM

 

General

*Walk fields to check general field condition, weed, vertebrate and other issues

*Watch for crop maturity, stand assessments, weed escapes, nutrient deficiencies, lodging issues

 Alfalfa:

*Evaluate established legume stands for approximate days until harvest
*Monitor potato leafhopper, foliar, systemic and crown rot diseases.
*Monitor new seedings for potato leafhopper, pythium blight, phytopthora root rot.

Small Grains:
*Monitor grain fields for growth stage, disease and lodging issues, grain maturity, harvest timing
*Record diseases present, location and types of weed escapes

 Corn:

*Monitor for mid-season corn pests including European corn borer, corn rootworm, western bean cutworm, slugs, foliar diseases such as northern corn leaf blight and gray leaf spot, weed issues, nutrient deficiencies, vertebrate damage.

 

 Soybeans:

*Monitor for soybean aphid, defoliators, foliar diseases, white mold, weed issues, vertebrate damage

 

 Pastures:

*Check water sources, mend fences as needed.
*Check crop growth, clip pastures between grazing as needed
*Monitor for invasive species, plants harmful to livestock
*Review/Plan rotations

 

Storage:

* Check stored grain bins for temperature, moisture and signs of mold and insects. Aerate, core, transfer grain or treat as necessary

* Clean and disinfect empty storage bins in preparation for grain harvest
*
Check forage allocation and anticipate feed program adjustments as forages from previous year are used up
*Mow around storage bins and facility to minimize pest hiding places

 

Dairy Cattle Barn Fly Management:

*Monitor animals and barn area for house fly, stable fly and other pest management needs including presence of rodents and birds.
*Check facilities for favorable fly breeding conditions: (organic matter + moisture): leaks in watering systems, roof gutters for leaks and potential overspill, drainage,
*Sanitation, sanitation, sanitation – clean animal resting areas, feed troughs, minimize source of moist organic matter i.e. fly breeding areas in barn and in adjacent animal loafing yard
* Continue fly monitoring: install “3X5″ index card fly speck monitoring cards throughout barn
*Use, replenish, replace fly management materials: sticky fly tapes/ribbons, insecticide baits, natural enemies (parasitoids), fly population monitoring (3 x 5) spot cards
*Consider purchase and release of Muscidifurax raptor and/or M. raptorellus natural enemies of house and stable fly pupae.

 

Dairy Cattle on Pasture:

*Monitor animals for presence of face flies, horn flies and stable flies. Action guidelines: face flies (average 10 per animal face), horn flies (average 50 / dairy per animal side, 200 / beef cattle per animal side), stable flies average 10 per animal (all four legs)
*Check feed bunk / water source locations for signs of stable fly breeding (moist undisturbed organic matter – spilled feed, round bales, etc.), minimize source of moist organic matter i.e. fly breeding areas in barn and in adjacent animal exercise yard.
*Check pasture for forage quality / quantity, rotate as appropriate
*Check pasture for vegetation poisonous to livestock
*Consider use of pasture fly traps to help reduce deer, horse and stable fly populations