Now that Poncho™ is available as a seed
applied insecticide for this year's planting season, it is important to consider
the management practices that will contribute to a good plant stand and high yields.
The obvious question that producers have been wrestling with over the past few
months has been whether to purchase the treatment option on their seed corn orders
or not. For growers who often struggle with seedling insect pressure from wire-worm,
European chafer, white grub, cutworm, etc., or growers who are on the lighter
textured soils that often face insect pressure, or growers who have corn following
crops of pasture or hay etc. the decision is probably straight forward. You either
have some drill box treatment which includes lindane that you can use for the
last time this year or you purchase seed with the low rate of Poncho (250) because
you realize the
European chafer and damaged
corn plant (T. Baute, OMAF)
potential to have losses far outweigh the cost of the seed treatment. For those
growers who have little experience with insect pressure causing any problems in
the past, have never been too keen on handling the seed box treatment insecticides,
and even questioned the effectiveness or returns of insecticide seed treatments,
the question becomes a bit more challenging. Do I invest 7-8 dollars per acre
as insurance against potential insect damage? Granted, there has been some research
that has suggested a reasonable yield advantage to the low rate Poncho treatment
even in the absence of a particular pest (i.e. wireworm, chafer, corn rootworm).
I suggest that your best response in these situations is to put the seed treatment
to the test in some side-by-side comparisons in fields where you may not typically
expect an insect problem - say in medium to fine textured soils where corn follows
soybeans. This will require you to get the same hybrid treated and untreated and
to do some split planter comparisons in order to improve your decision making
ability in the future. In the case of corn after corn where producers have been
using in-furrow insecticides, the high rate Poncho (1250) seed treatment will
be similar in effectiveness in controlling corn rootworm as these other products.
Here the decision needs to be based on price, availability of the treated hybrid
you desire, and your level of comfort in purchasing and handling the in-furrow
insecticides. Finally a few comments on the planting operation itself, if you
have purchased insecticide treated seed. Seeds treated with insecticide flow through
the planter differently than non-treated seed. Vacuum planters will tend to under
seed, while finger planters will tend to over seed. To accommodate the seed flow
of insecticide treated seed, seed lubricants must be used to ensure desirable
results. This means a little more attention to using the graphite in finger planters
and talc in the vacuum units. Occasionally, check the seed meter parts for the
accumulation of seed treatment. Generally, a build up of seed treatment on these
components indicates a need for more lubricant. This will be more often be the
case in high humidity situations. Also be aware that Poncho treated seed may require
the adjustment of vacuum pressure to improve the accuracy in seed metering. In
work done with a John Deere vacuum planter, indications are that seed size plays
a role in the need to adjust vacuum settings. Round seed, whether medium or large,
that had been treated with Poncho, did not seem to require adjustment of the vacuum
setting in order to seed at a rate similar to untreated seed. Flat seed however,
required an upward adjustment in vacuum (1-2 psi) in order to plant treated seed
at a rate similar to that achieved with untreated seed.
