Greetings Rye,
I believe this term is a carry over from a time when pest management
applications would 'cover' the commodity in a blanket of spray
following the critical petal fall application. This PF event
typically occurs at roughly 80% of the petals falling from a variety
such as Mcintosh in apple. At this point in time the flowers loose
their attractiveness to bees allowing for insecticide pest management
to occur.
In New York's Hudson Valley, this application of insecticide will
control European apple sawfly, plum curculio, the overwintering stage
of obliquebanded leafroller, tarnish plant bug, rosy apple aphid, and
others, depending on the insecticide used.
Typically insecticide applications follow a 10 to 14 day interval
called cover sprays or covers for short, depending of course on
insecticide longevity and the weather (OP's longer, Bt's shorter).
The residual of the previous application carrying over for this
interval based on its residual to withstand weathering or hydrolysis,
its U.V. stability and so on.
These applications then target the same insect (PC for the 1st and
possibly 2nd cover), or a different insect species or complex of
insects (such as codling moth at 2nd, SJS at 3rd cover; summer
generation of OBLR at 4th cover; apple maggot & SJS at 5th -7th
cover) at different periods relative to their timing after petal
fall. All of which depends on pest management strategies, weather,
population density to name but a few of the variables that increase
or decreasing the timing interval.
Regards,
Peter
Hello all,
I'm looking over pesticide information and I see a lot of references
to first cover, second cover and third cover and also references to
first cover spray, second cover spray and third cover spray. All
references seem to expect the reader to know what that is.
Searching the web I found one reference that said second cover is
4-6 weeks after petal fall. Another reference seemed to refer to
the number of wet days to get to second cover and that didn't make
any sense to me at all.
I guess I'm really unclear on what "cover" means in this context.
What does the term refer to? What is being covered at these stages
and/or what is doing the covering? Or what observation do you make
and say "ah! we are reached second cover today!" (same question
for first and third.)
Also, what is the relationship between "second cover" and "second
cover spray"? (same question for first and third) I think I would
understand once I understand what second cover is, but my general
confusion on the topic leaves me with little confidence in that.
I have found references for definitions of some stages such as green
tip, pre-pink, pink. But these "cover" stages elude me.
Thanks for sharing your expertise!
Rye Hefley
Future Farmers Marketer
So. Cal.
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--
Peter J. Jentsch
Senior Extension Associate
Department of Entomology
Cornell University's Hudson Valley Lab
3357 Rt. 9W; PO box 727
Highland, NY 12528
email: p...@cornell.edu
Phone 845-691-7151
Mobile: 845-417-7465
http://www.nysaes.cornell.edu/hudson/faculty.php
http://www.nysaes.cornell.edu/ent/faculty/jentsch/
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