Managing Flies on Dairies

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Managing Flies on Dairies

• Kelly V. Tindall
• Extension Entomologist
• Twin Falls County

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Problems with House Flies

• Nuisance
• obnoxious to workers nearby residences
• Public health issue
• Transport gt100 associated pathogens
• garbage, sewage and other sources of filth
• transferred by mouthparts, body parts, feces, etc
  
• humans and animals
• typhoid, cholera, bacillary dysentery,
  tuberculosis, infantile diarrhea, parasitic worms

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House Fly Life Cycle
Adults attracted to organic matter
Lay eggs
Cycle takes 10-21 days (as little as 7 in right
conditions)
Adults emerge from pupae
Larvae hatch feed on organic matter
Adults live about 30 days Female lay up to 900
eggs
Larvae crawl to a drier area to pupate
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Management Techniques

• Integrated Pest Management (IPM)
• Management of pests that incorporates many
  practices for environmentally friendly and
  economically feasible control
• Physical/Mechanical sticky traps, fly swatter
• Cultural proper sanitation
• Biological parasitoids, predators
• Chemical insecticides

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Reliance on Insecticides

• Elimination is impossible
• Select for insecticide resistance non-control
• New, effective insecticides are few
• Concern about residues in livestock products,
  worker health and safety, and the environment

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Mechanical Control

• Sticky tapes, paper, ribbons
• Large sticky products are effective small to
  moderate populations
• Fly-free zone in the milk room
• Tight-fitting screen doors and windows
• maintaining tightly closed can greatly reduce fly
  numbers

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Monitoring

• Baited traps - gallon milk jugs
• Four 2-inch holes cut
• Bait inside bottom of jug (entrance)
• Attractant (muscalure) insecticide
• Suspend from rafters
• Minimum of 5 at equidistant locations throughout
  each animal housing unit
• Count flies after 7 days
• gt250 flies/week high levels of fly activity

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Monitoring

• Spot cards
• 3X5 inch white file cards
• Placed on resting surfaces
• look for areas fly fecal and regurgitation spots
• Minimum of 5 at equidistant locations throughout
  each animal housing unit
• Count flies after 7 days
• gt100 spots/card per week high levels of fly
  activity

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Cultural Control

• Most important - reduce ability to breed
• Identify breeding sites
• Monitor regularly
• Eliminate/reduce breeding sites
• General suggestions
• Stop water leaks promptly
• Manage feed storage areas
• Maintain adequate ventilation dry manure

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Potential Breeding Sites

• Calf hutches (corners)
• Silo leak spill areas (silage)
• Animal stalls pens, feed preparation, storage
  manger areas, water sources
• Calf, hospital, maternity areas
• Water tanks
• Feed troughs
• Inside and outside manure handling areas

http//www.nysipm.cornell.edu/factsheets/dairy/bar
nflies/breed_sites.asp
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Cleaning Guidelines

• 1 problem animal pens
• 1st Calve hutches
• remove manure bedding at least 1/week
• 2nd Free-stall barns
• Design for complete manure removal proper
  drainage
• Moist feed near storage and feeding sites
• clean out at least weekly

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Biological Control
Mites - eggs
Wasps - pupae
Beetles - eggs
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Biological Control

• Parasitoids - most important
• Climate impacts efficacy
• Preference for different breeding habitats

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Parasitoid Life Cycle
Parasite searches for fly pupae
Parasite drills a hole in a pupa and lays eggs
(usually kills pupa) Multiple eggs in per pupa
1 female kills 100 fly pupae
Egg to adult takes 2-3 weeks
New adult parasites emerge
Eggs hatch immature wasps eat pupae from the
inside out
Pupate
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Relationship of Fly Parasitoid Life Cycles
1 Wasp 100 dead pupae SO 9 wasps/fly
7-21 days
14-21 days
1 fly 900 eggs over 30 days
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Biological Control

• Parasitoids - most important
• Climate impacts efficacy
• Preference for different breeding habitats
• Flies have advantages to get ahead of parasitoids
• develops twice as fast from egg to adult
• lives longer, and lays more eggs than parasitoids
• More tolerant to insecticides than parasitoids

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Hints for Parasitic Wasp Success

• Get species appropriate for Idaho
• Best results with manure management and other
  tactics
• Because of differences in fly and parasite life
  cycle, multiple releases must be made
• Early use helps prevent rapid growth of fly
  populations AND increase parasitoids populations
• Minimize negative insecticide impacts
• Select baits and pyrethrin space sprays

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Dollars Sense of Wasps

• How many parasitoids should be released?
• 200 parasitoids per milking cow / week
• 1,000 parasitoids per calf / week
• Adjust to find effective and affordable rates
• When should parasitoids be released?
• At the first sign of fly activity (mid-April)
  through fall (late Sept early Oct)
• Early release helps keep fly numbers down

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Dollars Sense of Wasps

• Are parasitoids cost effective?
• Prices vary, average is 11-13/10,000
• Rate of 200 per cow 0.22-0.26/week
• 1000/hutch 1.10-1.30/week
• Cost of parasitoids is offset by reductions in
  insecticide treatments
• IPM vs non-IPM fly control
• 80 fewer insecticide treatments
• Fly populations are 50 lower

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Chemical Control

• Chemicals are important BUT not the only tool
• Overuse fly resistance and kill beneficials
• Baits contained insecticide used with an
  attractant
• Treat areas where adult flies congregate
• Avoid spraying breeding sites and residual
  premise sprays (protect beneficials)
• Combination of multiple methods is more effective
  and provides more sustainable control

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Chemical Control

• Space sprays
• Quick knockdown in an enclosed air space
• Little residual
• Compatible with fly parasitoids
• Baits
• For managing moderate fly populations
• Compatible with fly parasitoids
• Residual premise sprays
• Treatment of building surfaces with residual
  sprays has been one of the most popular
• Many reported cases of insecticide resistance

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Chemical Control cont

• Larvicides
• Direct treatment of manure
• Avoid to protect natural enemies of flies
• Occasional spot treatment of heavily infested
  areas
• Controlled-release formulations
• Feed additives/minerals that result in the
  insecticide's being excreted with animal feces
• Whole-animal sprays
• Sprays made directly on the animals
• More for stable fly control
• Control is short-lived

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Questions?