Hi Debbie –
It is best to release Fly Parasites throughout the season for several reasons: pests produce more eggs in a shorter period of time since their life cycle is much shorter and flies come in from elsewhere. Also, releasing small amounts of Fly Parasites over a period of time (weekly, every other week or monthly) has proven to be more effective than a large release.
For best results, start releasing before flies become a problem. If pest populations are high, use a least-toxic, short-lived natural pesticide to establish control before releasing the predators. Here’s a list of our recommendations:
• Sanitation is the most effective and important step in reducing pest numbers.
• Dry and wrap organic waste before placing it in the garbage can or compost bin. Seal garbage cans with tight fitting lids.
• Hang The Big Stinky or other pesticide-free traps outdoors near problem areas — barns, kennels, garbage bins — to capture pest flies and reduce the number of egg-laying adults.
• Food-grade diatomaceous earth is a mild abrasive that works within 48 hours of contact to kill soft-bodied maggots. May also be applied to moist areas where its sorptive qualities effectively reduce breeding sites.
• Least-toxic botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
For more information please visit our page on how to get rid of flies naturally.
Hope it helps!