Viruses - everyone’s heard more
than they want to know about them. Many growers know someone who has dealt with
one. But what if we changed the narrative? Not all viruses are harmful. Gemstar LC is one such example. Gemstar LC is
a baculovirus insecticide that contains a naturally occurring virus that
infects and kills larvae of the
Helicoverpa or
Heliothis spp. With
this very host-specific virus, beneficial insects, fish, wildlife, livestock, and
humans are left untouched while pest species are devastated.
Originally developed for use on
sweet corn, the label has recently expanded to include hemp. Hemp crops can be
severely damaged by the following, virus-vulnerable pests:
- Corn Earworm
- Tomato
Fruitworm
- Cotton
Bollworm
- Tobacco
Budworm
While federally registered for hemp,
Gemstar LC is also on many of the state lists approved for use on
cannabis. Gemstar LC can be used late in
the crop cycle without residues remaining in the harvested bud. Gemstar LC can be used the day of bud harvest
with just a 4-hour REI.
Gemstar LC must
be eaten by the larvae to be effective. Gemstar LC is most effective against
first or second instar larvae, so a scouting program to detect pests very early
in the season is recommended. Frequent application at lower rates is more
effective than infrequent applications at higher rates, to give larva ample
opportunity to consume the virus. Other pesticide products, such as BTs, have a
similar mode of action. Combining these products will not increase efficacy, so
choosing just one is best.
Death is not immediate - it may
take several days to see results. Once
dead, the insect releases millions of virus particles to potentially infect other
insects that come in contact with the cadaver. In summary, this good virus
reduces the need for harsh insecticides during a critical part of the crop
cycle.
Some
keys to effective results with Gemstar LC
- Label
rates are 4-10 oz; use the higher rate for higher insect pressure.
- Gemstar
is sensitive to direct sunlight; spraying is best done at times where the
sunlight is not as direct like late afternoons, evenings or cloudy days.
- Complete
spray coverage is important; typical spray volumes range 20-100 gallons
per acre with more required for larger plants.
- Do not
use silicone-based spreaders
- Use of
methylated seed oils, latex, humic acid even powdered milk have been shown
to enhance effectiveness
To learn more about Gemstar LC
reach out to your Griffin sales rep or the GGSPro team to find out how a
beneficial virus can enhance your insecticide program.
