Natural pest control

with AG’s gardening expert Ruth Hayes

I am using GroGreen Feed & Shine Roses on our roses this year

Lily beetles demolish lily plants

Removing blackfly by hand

Pest control, naturally

Chemicals aren’t the only way tackle pests, says Ruth

UMMERTIME, and the living is easy if you are a garden pest, merrily chomping your way

Sthrough new plant growth.

It is a constant battle to keep plants healthy and pest-free, but it can be won by consistent plant care and paying attention to what’s going on out there.

I prefer to avoid chemical sprays, instead using careful husbandry and harnessing the power of natural predators (including birds, hedgehogs, ground beetles and hoverflies) to keep plants strong.

On the rare occasions I do use chemicals I use organic sprays, such as the widely available Neudorff Bug Free or Vitax Plant Guard.

I also use some of the newly released plant invigorators, including rose and buxus sprays made by Westland and GroGreen. These supplement the feeding and watering regimes, and help keep plants robust and more able to fight off problems. Regular weeding is also important as it not only keeps borders tidy, but also removes hiding places where pests like to lurk.

If you do prefer to use synthetic chemicals, such as Resolva Bug Killer or Provanto Ultimate, always follow the manufacturer’s instructions carefully.

Don’t spray plants indiscriminately and never use them on a windy day as the poison will be blown around the garden and will kill pollinators, which are

I have found Grazers G4 very efficient at deterring lily beetles

G4 tested

We put beetle deterrent to the test n Our two pots of lilies overwinter in the greenhouse and spend summer on the patio. n Each year they are beset by lily beetles, and each year I spray them with Grazers G4 deterrent to keep them safe. n I find it works excellently, while also keeping the beetles in the food chain for hungry birds. n This year, to prove its efficacy, I plan to spray just one pot, leaving the other one unprotected. n It’s an unscientific test, but one that will hopefully prove conclusive. n It will also hopefully demonstrate that you can protect plants by using something other than chemicals that not only remove pests, but also prove fatal to the insects we and the garden needs. These pollinators and predators include ladybirds, beetles, wasps and hoverflies.

already under threat, and useful insect predators. Most importantly, never use any chemicals on flowering plants, which is where most insects are heading now.

Controlling pests under glass and indoors

WHILE greenhouse plants are, to some extent, protected from many pests, they have their own set of problems.

Dry air encourages greenhouse red spider mites, which suck plant sap, create webs, cause mottled leaves and weaken plants. Whitefly also suck sap and can spread disease, while tomato moth caterpillars chomp away at plants and fruits, and often go unseen until you spot their trails of droppings.

Biological controls work well under glass. They are parasites and predators that thrive in warmth and die off once the temperature drops or they have exhausted their food supply.

Encarsia formosa, a tiny wasp, will cull whitefly, and there are predatory mites that make short work of red spider mites. Check tomato plants for caterpillars and pick off any you find.

Yellow sticky papers do a thorough job, but will also trap beneficial insects, so I avoid them. I am, however, quite tempted by a carnivorous butterwort plant that ensnares small insects.

Placed indoors, I am hoping it will make a meal of the fungus gnats lurking

Butterwort as a fly catcher!

Encarsia formosa keeps your greenhouse free of whitefly

in our houseplant compost! Visit  greengardener.co.uk or call ✆ 01493 750061 for biological controls.