Current Planting, Currant Pests and Wireworms

Planting now? With that really good warm day yesterday, I know you are ready to plant everything—but whoa! There is no point in trying to rush warmth-loving plants, such as tomatoes, peppers, squash, cucumbers, corn, beans, into the garden as it is still too cool for them. Indeed, cool weather crops (cabbage family, peas, lettuce, onions, leeks) now in the garden are growing slowly enough as it is, though they are finally picking up speed with the warmer temperatures this week. When tomatoes can go outdoors is debatable: they are generally more robust than the other tender plants and some varieties can take pretty cool weather. It doesn’t mean that they grow much, just that they tolerate it. Varieties such as ‘Oregon Spring’ and ‘Siletz’ can set fruit at 10oC [50oF], but the big, potato leaved varieties, such as ‘Brandywine’, need seriously warm weather to do well. If you have already set out your tomatoes, do what you can to keep them warm at night, whether it is using floating row covers or cloches. If the undersides of the leaves are turning purple, it shows the plants are suffering from a phosphorus deficiency caused by being too cold. They should grow out of it when it warms up.

On the strength of a few sunny days coming up according to the forecast (or will it be another mirage of sunny days that don’t quite arrive?) I am starting beans and my first planting of sweet corn (indoors). I hope the soil will be warm enough when they are ready to be set out later in the month.

If you are planning to grow winter cabbages, such as January King, Langedijker Red, Danish Ballhead and other varieties that take 100-120 days to produce full-sized head, be ready to sow those no later than the end of May. For later sowing, there are many other cabbage varieties that don’t take that long (for example, savoys generally mature in 65-80 days). Also be ready to seed Brussels sprouts no later than June 1 as they also take 90-100 days. Some people get caught out every year with Brussels sprout plants too small in the fall to make sprouts—so this year, get going earlier.

Wireworms: These seem to be more numerous than usual this year, at least in some gardens. If wireworms are big enough to see easily, they are several years old, since it takes 4 or more years for them to develop from egg to adult (called a click beetle). The larvae bore into roots and tubers, large seeds (such as corn), and roots of many seedlings. Right now, steadily eliminating my lettuce plantings is what they are up to in my garden. For the first time in years I have had to resort to potato traps to clear the soil before planting. First remove all crop debris and weeds from the soil. Then use chunks of potato or carrot to attract wireworms. I skewer each chunk on a short stick so I can find it again, then bury it a couple of inches deep in the soil. Pull up the traps every day or two and destroy any wireworms in the bait. Some will be stuck right into the potato, while others may be lurking in the soil beside the bait. It is best to use a trowel to lift up the bait chunk so you can spot the nearby wireworms. You can reuse the potatoes for a couple of weeks. A chunk of potato every square foot or two over the garden bed attracts a lot, but still keep watch for stray wireworms as you prepare the bed for planting. For photos of wireworms, damage and potato traps see.

Good news with respect to spring pests is that I haven’t been finding any more cutworms in the soil: just their pupae (those mahogany coloured ‘bullets’), so that source of leaf damage is over.

Prevent currant & gooseberry pests: If you have had leaves of currant and gooseberry bushes chewed up in the past years, now is the time to control the eggs of Imported Currantworm (the caterpillar-like green larvae that does the damage). Eggs of this insect are laid from mid-April (warm years) to end of May (cool years). All you have to do is inspect leaves in the central and lower part of the bush for eggs or groups of little green larvae feeding together. There is only one generation per season so catching the leaves with eggs or larvae right now is the end of the matter for this year. For photos of damage and what the eggs look like on the leaves, see.

The other pest that afflicts these plants is the currant fruit fly. Nothing like tiny compost fruit flies, these flies are larger and only have one generation per year. By covering plants during the 3 week egg-laying period in the spring, you can avoid damage entirely. Starting by mid-May, cover plants with sturdy insect netting and leave them covered until mid-June. ProtekNet is the main product available locally; it is knitted monofilament poly, tough and tear proof. Cover the whole plant and tie the netting into the trunk so that nothing can get in from the bottom. After mid-June, you can remove the netting. For photos of egg marks on unripe currants and fly larvae, see. Local nurseries that I know are selling ProtekNet: Chorus Frog on Salt Spring; Russell Nursery, Sidney; Dinter Nursery, Duncan. If you know of any others selling this or a similar product I would appreciate hearing from you so that I can let people know.


About Linda A. Gilkeson, Ph.D.

Salt-Spring---Linda-GilkesonLinda earned a Ph.D. in Entomology from McGill University in 1986, then moved to British Columbia to work for Applied Bio-Nomics Ltd., a company that produces biological controls. From 1991 to 2002 she worked for the provincial government, promoting programs to reduce and eliminate pesticide use. She was head of the provincial State of Environment Reporting Unit for the next six years, then the Executive Director of the Salt Spring Island Conservancy until the end of 2011. Linda now devotes her time to writing, teaching and consulting.

Linda has co-authored pest management training manuals for the government and organic gardening books for Rodale Press. She has self-published two books: Year Around Harvest: Winter Gardening on the Coast and West Coast Gardening: Natural Insect, Weed and Disease Control. Her recent book, Backyard Bounty: The Complete Guide to year-Round Organic Gardening in the Pacific Northwest, has become a BC best seller.

As a private consultant, Linda is a regular instructor in the Master Gardener programs in BC and is busy year around giving workshops on pest management and organic gardening.

Linda has served as President of the Entomological Society of Canada, the Professional Pest Management Association of BC, the Entomological Society of BC and the Salt Spring Island Garden Club. She was awarded a Queen’s Jubilee medal in 2003 and an outstanding achievement award from the Professional Pest Management Association of BC in 2005.

Follow Linda's work at­­­­­­­­­­­­­­­

May 9, 2017 5:21 PM

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