When is the right time to start my fly control?

 

One of the big issues that intensive farmers face is the battle against fly infestation. Flies breed quickly, with female flies laying between 100 and 150 eggs per cluster. If conditions are favourable, a female can lay up to 20 batches of eggs in their lifetime. These eggs will then begin to hatch within hours, producing grey/white larvae that start to feed on any available organic matter.

These larvae are highly mobile and grow rapidly. Within as little as four days, they are seeking out cool, dry areas to pupate. In warmer conditions, this stage can last 3-6 days before a fully grown, sexually mature adult fly emerges. These adult flies will seek out areas of moist matter and decay to begin the breeding process. The females will lay eggs and repeat the cycle over the next 2-20 days, causing the fly population to multiply exponentially if left unattended.

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Flies are carriers of disease and bacteria, so it’s important to stay on top of the fly population to protect your livestock. Given the rate at which flies can multiply, the best action is prevention. Preventing growth and development of the fly at the larvae stage can forestall a full infestation of flies, which can be harder to regain control of.

Common problems on farm:

The main problem which we come across is that producers don’t start with their fly control until they have fly issues in their egg collection room. At this stage, the flies have already got the upper hand.

The second problem we find is that people also judge fly seasons on external temperatures, instead of our reasonably constant temperatures inside our poultry units 12 months of the year.

The third issue we regularly come across is insufficient product use, and therefore an ineffective application.

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FAQs

"What is a larvicide?"

A larvicide is an insect growth regulator, which controls the development of fly larvae. The most common and effective fly larvicide is Cyromazine, which works by affecting the nervous system during the immature larval stage of the fly.

 

"How often should I treat the muck with a larvicide?"

The first application of larvicide should start around 2-3 weeks after birds are housed, or when the floor area under the slats is covered in muck. Reapplication is then determined by a monitoring system that should be put in place, which can be a simple measuring stick with 10cm (4 inch) marks pre-marked on the stick. Fly larvae live in the top 10cm of the muck at all times, so you should re-apply you larvicide treatment every 10cm of muck build-up.

 

"When should I start treating with a larvicide?"

If you have birds housed already and do not have proactive fly control program already in place, you should start your first larvicide treatment of the year no later than February, and start monitoring the muck from there. If you are considering a fly control program for a new flock, the first application of larvicide should start around 2-3 weeks after birds are housed, or when the floor area under the slats is covered in muck. However, your fly control program should start prior to the birds being housed, particularly in a flat-deck or deep pit system. This can be done by painting adulticides on boards (such as LD100A or Fly Select). These can be hung from the slats ready to catch any adult flies before they come through the slats to the bird area.

 

"What is the best method of applying a larvicide?"

There are three methods to apply a 2% cyromazine-based larvicide, such as Zero:

  1. Knapsack sprayer (500g/5L water)
  2. Watering can (500g/5L water)
  3. Dry scatter the product onto the litter

The key part to application is ensuring you distribute 500g of 2% Cyromazine per 20m² floor area. Our preference is watering can application, which provides a generous amount of liquid to help soak through the top 10cm of muck. However, if the litter is already wet, dry scattering would be more beneficial.

 

"Why haven't I yet seen a reduction in fly numbers after recently treating with a larvicide?"

It can take 2-3 weeks to see an indent in the fly population after the application of Zero (2% Cyromazine), as it does not work on the later pupae stage. If you have a particularly bad problem, you may need to treat twice.

The importance of monitoring

Regular and systematic monitoring of adult fly and larval populations is an essential requirement to measure the effectiveness of control systems and to provide an early warning of a potential problem.

Monitoring of adult fly and larval populations should be undertaken at least twice a week during the fly breeding season – between the beginning of April and the end of October, and once between November and March.

A number of 1m² monitoring squares, (six for large houses) should be marked out along the inside walls and undersides of walkways in areas where flies are known to rest. The number of flies resting within the squares should be counted on a regular basis.

There should also be six designated areas within the manure, around 0.5m² in size, in which larval activity is monitored. Areas chosen should be where larval activity is more likely, such as around drinkers and posts, or other areas where the manure is more moist. The same areas should be used throughout the season, where practical.

 

The top 4 inches of the manure should be investigated on a regular basis. The percentage of the area containing larvae should be assessed as follows, and treatment should be triggered:

0 = zero larvae

1 = less than 10% of the area contains larvae

2 = 20% of the area contains larvae

3 = 30% of the area contains larvae

4 = 40% of the area contains larvae

5 = 50% of the area contains larvae

 

Interhatch offers a complete range of products to help control flies on your farm, at every stage of their life cycle. All products can be viewed on our website, or you can contact one of our specialists for any advice and support.