Sunflower head moth

Chemical control should be considered during te R5.0-R5.5 growth stages no scouting is needed until bloom stage.  It is critical that the insecticide is applied before the eggs have been laid.  Treatment should be considered when 20-40 percent of the plants have reached flowering (R-5.1).  Preventitive insecticides can be used prior to bloom.  Once the larva hatch, during flowering, they will burrow into the seed where they will feed and take refuge.  As soon as the heads begin to fill they will get heavy and bend face down towards the ground also creating protection from insecticides.  Usually no applications are applied beyond this point.  There is a small window to which timing is crucial.  If popultions rebound from the first application then a second application might want to be considered.  With heavy infestations an interval of 5-7 days is recommended for control.

Yield losses occur due to the feeding on the seed from the larva.  As an indirect effect of the damage caused by the larva Rhizopus head rot can enter through the feeding wounds and can potentially cause total head loss.  It is estimated that 1-2 mohts per 5 plants is the economical threshold.  Head moth are best scouted for during dusk and nightime.  The sunflower head moth are less active during the day but activity during the day may suggest that threshold levels are high.

Possible Insecticides and Rates:

Insecticide	Rate
Beta-cyfluthrin (Baythroid XL)	0.0155 to 0.022 lb. a.i./a (2.0 to 2.8 fl. oz.)
Chlorpyrifos (numerous products)*	Check label, but generally 1 to 1.5 pints/acre
Chlorpyrifos plus gamma-cyhalothrin (Cobalt)	19 to 38 fl. oz. /a
Deltamethrin (Delta Gold)	0.012 to 0.018 lb. a.i./a (1.0 to 1.5 fl. oz.)
Esfenvalerate (Asana XL)	0.03 to 0.05 lb. a.i./a (5.8 to 9.6 fl. oz.)
Gamma-cyhalothrin (Proaxis)	0.01 to 0.015 lb. a.i./a (2.56 to 3.84 fl. oz.)
Lambda-cyhalothrin (numerous products)**	0.02 to 0.03 lb. a.i./a
Parathion, methyl (Cheminova Methyl 4EC)	1 lb. a.i./a
Zeta-cypermethrin (Mustang MAX EC)	0.014 to 0.025 lb. a.i./a (2.24 to 4.0 fl. oz.)

References:
http://www.entomology.ksu.edu/DesktopDefault.aspx?tabindex=345&tabid=547
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1109&context=extensionhist
http://elkhorn.unl.edu/epublic/pages/publicationD.jsp?publicationId=539
http://www.entomology.ksu.edu/DesktopDefault.aspx?tabindex=345&tabid=547