June 15, 2006 Volume 5 Number 9
1. View from the Field
2. Powdery Mildew on Wheat
3. Predators in Alfalfa II
4. Sampling for Potato Leafhopper in Alfalfa
5. Clipboard Checklist
6. Growing Degree Days in NYS
7. Up Coming Events
8. Contact Information
View From The Field
Julie Stavisky, NYS IPM
Ken Wise, NYS IPM
Alfalfa weevil injury is showing up in alfalfa re-growth!
I’ve heard reports from fields in Ontario county where feeding is
close to threshold. In Seneca County, a field was showing
50% tip feeding, and 2nd and 3rd instar larvae were observed.
Let’s review the alfalfa weevil (AW) guidelines following first
harvest: If more than 50% of the AW are in the cocoon stage, the
population is maturing to a non-feeding stage and will no longer
be a problem for this year. If the larvae are predominantly young,
however, damage may be expected, especially if the weather is cool
and dry. In addition to watching for cocoons of the AW, watch for
the cocoons of the parasitic wasps that keep AW populations in check.
After the first harvest, control measures are recommended when either
50% or more of the stems show signs of AW feeding, or there are
two or more larvae per crown.
Soybean rust sentinel plot sampling has begun across NY.
For regular NY updates, visit
New York State Soybean Rust Information Center, and for national
updates, visit the USDA Public PIPE
During an “Early Season Corn Pests” meeting led by Dean Sprague
in Chautauqua County this week, black cutworm was the star of the
show. Close to 5% of plants had been cut, but the larvae we
found were all larger than 1 inch. In an adjacent alfalfa
seeding, a lone potato leafhopper was observed.
Nancy Glazier conducted scouting for the Ontario County soybean
TAg team this week, and observed soybean aphid in only 1 field (where
they were originally observed last week). One soybean
field she is scouting was half grain corn and half silage corn last
year, and Nancy saw slug damage on 60-70% of plants in the area
that was previously grain corn. Little slug damage was present
in the silage area, where there was of course less soil debris.
This week at the Cornell University Research Farm in Valatie
there could be a possible issue with alfalfa weevil on alfalfa re-growth.
The larvae are still small (1st to 3rd instar) and tip feeding is
at about 10 to 20 percent. Remember that the 4th instar eats 80%
of the all the alfalfa an individual will ever eat. Since larvae
are still small, as they approach the 4th instar they could still
cause some economic loses to the field. Remember the threshold on
2nd cutting alfalfa is 50% of the plants show tip feeding.
Potato leafhopper infestation remains low at both the Cornell
University Research Farm in Valatie and the SUNY Cobleskill farm.
I found only a few individual potato leafhoppers in several fields.
There are plenty of weeds present in the Cornell University alfalfa
trials at the SUNY Cobleskill Farm. As you can see from the photograph
yellow nutsedge and velvetleaf are thriving very well. I think Julie
Hanson plans to spray these soon.
Peter Carey in Sullivan County is finding some black cutworm
damage in field corn. He indicated that damage was below the
economic threshold. Cutworm damage can appear as plants have been
cut off just above the soil surface. Most likely you would not see
cutworms during the day since they are a nocturnal pest. Black Cutworm
larvae vary in color from light gray to black with a pale brown
to black head. Larvae have a greasy, shiny appearance with coarse
granules present over their body. During the day larvae burrow into
the soil next to the corn plant. For more information on black cut
worm you can view an article I had prepared
earlier in the season for the pest report
During an organic soybean/winter and spring wheat meeting last
Friday, we observed Stagonospora nodorum blotch on the lower leaves
and on some of the flag leaves. Rainy weather conditions in the
area were expected to be favorable to disease development. After
close field inspection, we found only one small powdery mildew infection
on one plant. Fortunately, no scab (Fusarium head blight) problems
were detected. I will continue to collect samples from this
field for Gary Bergstrom to check for possible scab as the heads
mature. The organic soybean stands look very uniform, although weed
emergence has also been good. Growers were not able to use blind
cultivation because the ground was too wet and the weeds greened
up. Growers plan to row cultivate as soon as it is dry enough. No
soybean diseases were observed.
Powdery Mildew on Wheat
Julie Stavisky, NYS IPM
With as much wet weather as we’ve seen in many areas of NY, powdery
mildew has the potential to really take off in wheat fields.
If powdery mildew shows up, the first symptoms include white powdery
patches on upper surfaces of lower leaves. With continued
cool, wet temperatures, the white powdery patches can spread to
stems and upper leaves. Patches may turn to a dull gray color,
peppered with tiny black specks as the disease continues to develop.
A dense, lush stand that does not dry from dew and rain is at the
highest risk from powdery mildew. The greatest chance for
yield loss occurs when the flag leaf is infected. Follow this link
for photos of
powdery mildew symptoms.
Management of powdery mildew depends on planning ahead.
Varieties that are moderately resistant are recommended, as are
systemic seed fungicides. Avoiding excess nitrogen will prevent
the growth of an excessively dense stand. Foliar fungicide
sprays are generally not economical, though many factors including
plant stage of development must be considered. Although it
is likely too late this year to consider foliar fungicide sprays,
now is a good time to review the
Managing Diseases of Small Grains section and the
Guidelines for Wheat Fungicide Decisions section in the online
version of The 2006 Integrated
Guide for Field Crop Management.
Predators in Alfalfa II
Ken Wise NYS IPM
Lady Beetle Larvae
I have been asked many times if this is a pest! I have
also been asked if they bite! If you have never seen a lady beetle
larva they look rather intimidating. Some people think they look
like tiny alligators. So – to answer the questions above – they
are a very effective beneficial insect and beware if you are a food
source like aphids and other small insects – they do bite!
Lacewing (several species)
Adults feed in the evening or night on nectar, pollen, and aphid
honeydew. Larvae are very active predators of aphids and other small
insects in many agricultural crops. Adults are light green with
long, slender antennae, golden eyes and have large lace-like wings
that are 1/2 to 1/3 inches long. Larvae are called antlions, and
look like a little green-gray alligator. Antlions have sickle-shaped
jaws, that penetrate the prey, inject a paralyzing venom, and then
suck out the body fluids of the victim. The larvae will reach about
1/2" long before they pupate.
Damsel Bugs (Nabidae)
Damsel bugs, also known as “nabids”, eat small insect eggs as
well as aphids and mites. This insect uses a needle like mouth-part
to insert into its prey and suck out the insides. They are slender,
often yellowish-brown and about 8 -12 mm (3/8 to 1/2 inch) long.
The wings lie flat across the back, crossing at the tips. The abdomen
is slightly swollen and the body tapers toward a narrow, elongated
head. The adult female inserts white colored eggs into the stem
of the plant --only the egg cap shows. Damsel Bug nymphs are a little
smaller than their parents, do not have fully developed wings, but
otherwise resemble wingless adults in shape and color. Be a little
careful with damsel bugs because they are predators and can give
a painful bite to big and small alike.
Adult syrphid flies, also known as flower flies, like to
feed on nectar and pollen of several kinds of flowers. Many species
of adult syrphid flies look like bees. After the adults feed they
lay 100’s of white 1mm long eggs in the mist of aphid colonies.
Syrphid fly larvae are good predators of aphids and other soft-bodied
insects. Larvae are legless maggots that are green, yellow or gray
with a yellow or white stripe down their back. For pictures of syrphid
flies view this website:
Fourteen Spotted Lady Beetle or the Cream Spotted Lady-beetle
(Propylaea quatuordecimpunctata) is a European lady beetle. This
lady beetle was accidentally introduced to North America. Some people
think it was transferred on a ship in the St. Lawrence Seaway sometime
in the late 1960s. This lady beetle does feed on aphids but I found
no information on the amount they can consume. This is a small beetle
that is only 4 to 5 millimeters.
Sampling for Potato Leafhopper in Alfalfa
Ken Wise, NYS IPM
Scouting alfalfa fields is the key to early detection of potato
leafhopper infestations. Use a 15-inch diameter sweep net to determine
the potential risk a potato leafhopper infestation may pose to your
alfalfa. Scouting for potato leafhopper starts after the first cutting
of alfalfa (about the first part of June – i.e. NOW) till the first
fall frost. You will want to use a potato leafhopper sequential
sampling plan to determine if an infestation requires management
or not. The first thing to do is determine the height of your alfalfa.
Smaller plants are more vulnerable to potato leafhopper; thus there
are different action thresholds for different heights of alfalfa.
The second thing you will need to know is how to sample for potato
leafhopper. A sample consists of a set of 10 sweeps of the net.
A sweep is one pass in front of you as you walk through the alfalfa.
The return swing is counted as another sweep. Sequential sampling
reduces the time spent in each field and tells you whether to treat
(management action) or not treat (no management action). Sequential
sampling is particularly helpful in minimizing time required to
make a management decision in situations where PLH populations are
very high or very low. Use the following chart to determine potato
leafhopper infestation levels.
N= No management needed at this time
T= Management needed as soon as possible
Write down the number of potato leafhoppers for each sample taken
on the card. Add each sample to the next, keeping a running total
of potato leafhoppers. You will need to take at least 3 samples
using the sequential sampling method. On the sequential sampling
card “N” is defined as no treatment (no management) needed at this
time and “T” is defined as treatment (management) needed within
in a week. If the sample is smaller than the “N” number stop and
scout 7 days later. If the number of leafhoppers is larger than
the “T” number then management action needs to be taken within a
week. If the number of potato leafhoppers fall between “N” and “T”
then continue and take the next sample till a decision can be determined.
A guide with a printable version of the
Growing Degree Days in NYS
Ken Wise NYS IPM
Accumulated Growing Degree Days for March 1 to June 14
Base 48 F
Base 50 F
*indicates missing data
Growing degree Days for peak (50%) Occurrence of Alfalfa Weevil
Stage or Event
Accumulated growing degree days (48F base temperature)
(Note: for alfalfa weevil predictions use Base Temp of 48F)
Weevil season nearly over for 2006. The accumulated growing degree
model for alfalfa weevil predicts weevil 50% of populations are
at cocooning stage in many areas of NYS, signaling the end of weevil
season. In areas where alfalfa weevil populations were high this
season, continue to monitor windrow areas for indications of weevil
feeding. Recall the post-harvest threshold recommendation is: 50%
of alfalfa stems showing signs of weevil feeding, larvae are < 3/8
in, and three are few or no weevil cocoons.
Keith Waldron-NYS IPM
* Update crop records by field, including pesticides used, nutrient
inputs including manure, growth and development observations, other
* Watch for weed escapes, herbicide resistant weeds, growth stage
for cultivation opportunities
* Storage areas cleaned and ready to accept hay harvest?
* Determine plant populations, make notes on germination problems
* Gaps in row? Check for seed corn maggot, wireworm, cutworm, seedling
blights, birds, seed placement issues?
* Monitor for weeds, note presence of "who", "how many", "where",
* Adjust post emergence weed control actions
* Monitor winter grains for crop growth stage, insect and disease
- Note flowering / heading date
Alfalfa & Hay:
* Monitor alfalfa seedings for weeds, insects & diseases.
* Check established alfalfa stands for potato leafhopper, weed and
* Harvest alfalfa - first cutting, check windrows for signs of alfalfa
* Check stand establishment, weed control
* Gaps in row? Check for seed corn maggot, wireworm, seedling blights,
birds, planter problems, drainage issues?
* Check for soybean aphid on young soybean seedling
Dairy Livestock Barn Fly Management:
* 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
* Check water sources, drainage, roof gutters for leaks and potential
* Collect and evaluate "3X5" index card fly speck monitoring cards.
Record results for future comparisons. Replace with new cards
* Evaluate animals for stable fly harassment (10 stable flies per
* Replace fly tapes as needed, check insecticide bait traps
* Note any repairs needed for recently used equipment: tractors,
harvest equipment and wagons, etc. as they are cleaned and serviced.
* Calibrate manure spreaders - maintain records on amount spread
6 July-CORNELL SEED GROWERS FIELD DAY
For Seed Growers, Seed Treaters, and other Seed Professionals
Place: NYSIP Foundation Seed Barn, 791 Dryden Rd., Rt. 366, Ithaca,
NY, Time: 9:00 AM-12.00 noon (registration and refreshments available
at 8:30 AM)
JULY 12 -WEDNESDAY - ROBERT B. MUSGRAVE RESEARCH FARM
Aurora, NY (Poplar Ridge Road, connects 90 and 34B)
Julie Stavisky: IPM Area Educator, Livestock and Field Crops,
Phone: (315) 331-8415
Fax: (315) 331-8411
Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Phone: (315) 787 - 2432
Fax: (315) 787-2360
Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316