pIPMing Your Home Garden

Getting a well balanced ongoing Integrated Pest Management (IPM) system up and running on a commercial scale for an established cropping enterprise can be a complex process that may need refining over several cropping cycles. Fortunately, using the principles of IMP in your home garden is much easier, and it can be extremely rewarding watching natural enemies control all your pests in a beautiful, balanced and biodiverse garden. Let's get started!

First things first, put your spray bottle away – you won’t need it yet. Secondly, invest in a 10x hand lens (magnifying glass) available here. Keep in mind that 90% of life on earth is under 2 mm so if you don’t have a hand lens, you are going to miss most of it, and make it very difficult to check your garden properly. We are going to set your garden up to harness the natural control of a huge army of beneficial insects that all just want to eat your pests. The key to all of this is to include as many flowers, as sources of pollen and nectar, as you can amongst your crop plants. This will provide sufficient food to establish populations of insects called ‘natural enemies’ or ‘beneficial insects’. See “The Power of Flowers” page on this website.

It is essential that the flowers you plant haven’t been treated with Neonicotine (Group 4A) insecticides either as seeds, or as potted nursery stock. If you plant seeds that have been treated with neonicotine insecticides you will be exposing the very beneficial insects you are trying to encourage to one of the most effective insecticides that man has yet created that are toxic to bees, other pollinators and beneficial insects at extremely low levels. Furthermore, potted ornamentals may be treated with even higher levels of neonicotines, that when planted in your garden, the insecticides can move in soil water to adjacent plant and kill beneficials, not just in their own right, but also toxify plants growing next to them. Despite the potential fall-out, there is no legal requirement (at the time of writing) to label treated potted ornamental nursery stock, or seeds although they must contain a dye to indicate they are not for consumption. Some seed suppliers for the home gardener here in Queensland are beginning to stipulate that they haven’t been treated with neonicotines, so choose them, and contact your nursery and suppliers to check potted ornamental for insecticide treatments. For more information on neonicotines see ‘Neonicotines as the greatest threat to Australia’s Landscape Functionality” on this website.

If you have a garden like ours at home (Southern QLD) you are probably planting, harvesting and removing spent crop plants several times a year which makes it easier to add flowers in such a way that ensure flowers are present throughout the season.

If you have a garden like ours at home (Southern QLD) you are probably planting, harvesting and removing spent crop plants several times a year which makes it easier to add flowers in such a way that ensure flowers are present throughout the season.

Alyssum (Lobularia maritima) is a standard inclusion in natural enemy friendly gardens and there is plenty of research to supports its use, and our garden at home always has some flowering but there are plenty of others that can help. The best way to choose the best flowers for your garden will be by observation. Try different species and check them regularly for visiting insects.

Introducing insect-friendly flowers is a great way to get going but an even easier way to get flowers in the garden is just to let your herbs and vegetables flower. We have found things like flowering silverbeet (chard), chives, dill, fennel, coriander, carrots, cornflowers, cosmos, borage, broccoli, kale and cabbages as well as many other herbs and vegetables all have fantastic insect-pulling characteristics.

There is no substitute for time spent looking at insects in your garden and if you’re a keen gardener, you will already know this. In your home garden you won’t need the same rigid structure around your pest checking as you do in a commercial crop, but you will need a 10x hand lens to do it properly. All you have to do now is look at everything regularly. Firstly, check to see if you have a range of insects at your flowers, and get a feeling for the different types you are seeing. You don’t need to be an entomologist to do it, just observation skills and get a feeling for what you are seeing. Next check your veges for signs of anything unusual, it could be damage (eg new leaves curling), it's normally the first thing you see.

The first and most important step is to do nothing – don’t jump at shadows. As you have now provided food for your natural enemies you should start to see them in your garden. Look for ladybirds (except the 28 spotted ladybird beetle witch will eat your cucurbits), lacewings, and hoverflies, and especially took for their immature stages, (eggs and larvae) as they do most of the heavy lifting. One of the pillars of IPM is to accept that you need some of your pest to present in your garden to provide enough food to encourage natural enemies to stay and breed. Unfortunately, the instructions on most insecticides tell you to spray ‘at the first signs” of your pest. While this may seem a good idea, it means that you will probably need to spray again and again. For example, aphids on roses are often problematic but there are many natural enemies of aphid that will happily eliminate them for you if you let them. Look for ladybird beetles, and hoverflies (Family Syrphidae) adults, larvae and eggs (links to images). More importantly, look for mummified aphids (fig 5) if you start to see them, you can walk away from your pest aphids at least for now.

Slow the growth of the pest population while you wait for natural enemies to become established. Things like hosing aphids off you roses for a few days may give beneficial insects enough time to start working.

If you are still having pest trouble, browse the commercially available options from producers like Bugs for Bugs they have a comprehensive list of pests and their natural control options. Often you will only need one or two releases but speak to them to get advice.

If you still find you have a need to spray, select the softest option available eg, white oil, dipel, or pyrethrum. Always follow the products’ label, and ensure that you get really good coverage. What you shouldn’t do is spray a broad-spectrum insecticide (remember that we want to keep some beneficial insects). Check the ‘Insecticide impacts on beneficial insects section’ to make sure you are not damaging your natural enemy populations, by choosing the wrong product.