By learning to spot problems early, they can be treated before a pest or disease really takes hold and becomes debilitating to the plants involved. Anticipation can also pay dividends and often pest or disease attacks are linked to weather conditions or certain stages of plant growth. For example, Aphid (Greenfly) attacks often happen in late spring or early summer when there is plenty of soft new growth on plants and is often worse during a humid spell of weather. Many a time I have walked into the garden to see the new growth on a purple leaved Berberis embellished with lime-green aphids clustered on the growing tips, distorting them by sucking the sap! Rubbing the aphids off with your fingers is a gooey, organic cure but if the problem persists I spray lightly with a ready to use bottle of Provado. A few squirts are enough as this pesticide is systemic which means that the active ingredient will be taken up by the plant and protect it from the inside. Any aphids which consequently feed will be killed and protection should last for a few weeks. Although I pinch out the tops of my Broad Bean plants when they are in full flower, they always end up with the dreaded Black Bean Aphid – a fatter, messier relative of Greenfly. Ladybirds and their larvae love to feast on these but sometimes cannot keep pace so again I use Provado and try to spray just before I think the aphid will turn up so that no Ladybirds or their offspring will be harmed.
Slugs and snails are another problem in our garden and I am always mindful of imminent attacks on plants such as Day Lilies and Hostas after a good downpour of rain. I use the organic slug bait which is very effective and only needs to be used in small amounts but often. As soon as rain stops I go out and sprinkle a few handfuls of pellets around the garden. These are washed back into the soil as ferrous sulphate completely harmless to other animals and insects. There is another product called ‘Slug Gone’ which I will trial on my Hosta pots this year. The product is made from sheep’s wool which contains lanolin. It forms a protective mat as it expands on watering and irritates the underside of slugs and snails so that they are deterred from crawling over it.
Watering correctly is one way that plants can be helped to withstand attacks – especially from mildews which often occur when plants are put under stress from being too dry or too wet. Downy mildew is seen on the underside of leaves and Powdery Mildew on the upper surface as white patches. When at college we were taught to remember the difference as ‘downy = down / under’. Both can be caused by too wet or too dry conditions so a good mulch of homemade garden compost or well rotted manure to improve the soil helps enormously. I try to mulch the garden at least once a year usually in the spring when I can see the soil surface before it is filled with plants! Giving plants a good start in the garden by taking time to prepare the soil well is also important so I add homemade compost to the soil at this time as well. Containers should be watered little and often so that young plants do not get too wet until their roots are established. Once the plants are growing away well, they will need more water – up to twice a day in breezy, sunny weather – and I try to feed once each week through the growing season which also helps to strengthen the plants against attack. The dreaded Vine Weevil larvae are voracious feeders on the roots of many plants especially when they are growing in pots or containers. Vine Weevil are especially fond of Primulas, Heuchera, Fuchsias, Cyclamen and bedding plants. There is a product available called Provado Vine Weevil killer which can be watered onto pots and is very effective against these little white grubs. The biological control of microscopic worms called nematodes that will swim through the soil and seek out the grubs to kill and feed on them is also very effective but the soil must be kept moist after application and this product cannot be used until the soil is above a certain temperature in spring.
Vegetable growing is fraught with problems. The weather is either to wet or too dry, Potato Blight can strike after a humid, drizzly spell of weather, Flea Beetle can eat salad crops such as Rocket, Mustard and Radish leaves and mice will feast on peas and broad beans as they are germinating.
But for now my problem is the Sparrows eating my beetroot seedlings along with pea shoots that are (were!) just piercing through the soil. Shot gun anyone?