Time for pest watch
As the weather warms up, pests and disease resurface in the garden. Here are some of what to look out for.
Leaf curl is a source of much handwringing among peach, nectarine, and almond growers this time of year. Unless trees are sprayed in winter its distortions will appear on pretty much all of them sooner or later. It’s an unsightly disease but, in my experience, it hardly affects yield. Affected leaves are replaced with healthy ones within a month or so and fruit continue to fill out and eventually ripen. Given that the usual preventative treatment is copper, which is toxic to worms, and that the disease is generally innocuous, you may prefer to let nature take its course. If you can’t abide it, be aware that, like most fungi, it cannot be treated once established. Repeated winter spraying is the only reliable way to prevent or at least minimise it. So if the leaves are curly now you’ll just have to wait until next year. Brown rot ( Monilinia fructicola), on the other hand, is a heartbreaking pain in the backside that you have every reason to fear. But we’ll talk more about that in summer . . . An established worm farm can process impressive volumes of organic matter into vermicasts in weeks. A common problem is how to separate worms from vermicasts. The answer? Don’t. However crowded with worms the castings, most will be working away in and under the latest scraps. Any you lose will quickly be replaced, especially in the warmer months. This approach also means your worm-poo fortified beds will be equipped with a new workforce for aerating the soil – just mulch deeply if you want them to stick around. From now on, keep a close eye on citrus blossoms for signs of aphids. These sapsuckers can smother and consume much of a tree’s potential crop in short order, if left to their own devices. Aphids’ coldblooded disposition and preference for reproducing parthenogenetically – with no input from males – means the warmer the weather, the faster they breed.
Steel-blue ladybirds seem fond of the aphids found on citrus but, like all predators, are not in the business of exhausting their food supply. So if you want real results you’ll need to intervene. Hosing down the trees can work, but will likely knock off a lot of blossoms too. For best results use a spray of hot soapy water once a week until the problem is sorted. This can kill ladybird larvae, but only on a very local scale and the mature beetles usually survive.
Information courtesy of Get Growing and NZ Gardener magazine. Sign up at getgrowing.co.nz for more hints, tips, recipes, and fruit and vege growing advice.