Kevin H. Ganoe, Regional Field Crop Specialist, Central New York Dairy & Field Crops Team, Cornell Cooperative Extension of Chenango, Herkimer, Otsego,and Schoharie Counties
Weather Data for Week Ending Sunday, June 10, 2012
We ended the week of June 10 with corn looking yellow from cooler weather, night temperatures in particular. In Table 1 you can see the average temperature was 4-5oF lower than normal. It was amazing in the past two days to see corn with 80oF+ temperatures turn a nice dark green and grow a bit. GDDs remain above normal by 4-7 days. Table 2 shows there was not much
rain as we were behind for the week and remain only slightly above normal for the season. Hard to believe given the difficulty at getting some fields planted and a good drying day for hay over the past couple of weeks.
The early planted corn is at the V6 leaf stage with the growing point now above grown and developing a root system. The plant ready to go through a rapid growth phase.
It should take about 450 GDDs to get to that V5-6 stage and a new leaf should appear for every 70 GDDs accumulated.
Looking ahead it should take 1250 GDDs for 96-100 RM hybrids and 1300 GDDs for 101-105 RM hybrids to reach
tasseling/silking.
Armyworm
Several emails have been sent alerting you to the presence of armyworms in the area. Although the largest numbers of armyworms have been found in western NY you should continue to be on the lookout for local hot spots. There seems to be on going confusion over this spottiness which if you don’t have armyworms is a good thing. To be clear you may have armyworms in fields but your neighbor a mile down the road may not or vice versa.
Over the next week you would be advised to continue to check the fields where armyworms are most likely to be found :
1. grass or mostly grass hayfields especially those that are now second cutting fields and you may be looking at harvesting that second cutting soon
2. corn fields that were late planted into grass fields, notill or tilled ground or fields planted into small grain cover crop.
3. corn fields with grassy weeds, quackgrass and other perennials or even annual grasses like crabgrass. Fields that may be planned for post-emergence weed control and the grassy weeds get a little ahead have been a target in the past.
4. small grain fields
Look for armyworms to be on the ground and undercover during the day, they feed at night. They won’t be in the ground but under any material they can find to crawl under.
Consider treatment if grass hay fields are have a consistent population of 3-5 armyworms per square foot range. Don’t just look in one spot, you may find 5 and then look other places and find none. Recommendations in corn are for at least 3 per plant in the whorl and they are less than ¾ of an inch then consider treatment. There is no reason to treat in preventative fashion for armyworms if they are not present. Also questions have been raised about second and third generation armyworms. There are second and third generations of armyworms in a summer but have never been know to be a problem. When the moths for the second and third generation fly off there are many places they may find attractive to lay eggs and is never concentrated as in the first generation.
