Sustainable Horticulture

Pest Invasion Tests Sustainable Strategies

Posted by sustainable_hort on March 21, 2010  |  No Comments

Sustainability requires a careful, optimized use of a farm’s natural systems. Healthy soil, right plants in the right places, IPM strategies and diversity are all used in successful farms. It can and has worked.

But, add an outside/alien invasive force…plant, disease or pest…and that natural system is taxed and cannot respond initially. Response is possible, but it would take at least years, if not decades.

So, the story rapidly developing around the Spotted Winged Drosophila (SWD) deserved the Portland Oregonian’s huge two-word headline…”CROP KILLER.” You may have read or heard about it. This invasive, Asian pest is causing near panic on the West Coast and particularly here in the berry and fruit production areas of Oregon. Florida has also found the pest. Just type the pest name into your search engine to find numerous sites describing and discussing the SWD.

It first appeared last summer and devastated some berry and fruit crops with its “voracious” appetite for ripening fruit. Most flies prefer over ripe or damaged fruit, not ripening ones. The damage destroys the fruit with frightening speed. OSU and other researchers have jumped in. There is and will be an interesting story as scientists, extension and growers race to find some control strategy. It is especially difficult since wild blackberries are common around the edges of the rich agricultural areas, a perfect host plant for the SWD to live and thrive on. Add to this the variety of hosts within any urban environment, many of which are not treated or sprayed…this is a serious test.

What is the test? Well, more precisely, what are the tests?

First, can the agricultural/governmental infrastructure organize an effective response? Do they have resources to bring together an educated, scientific team from various inter-related fields? As a community, or state, we have slowing been strangling our agricultural depth at places such as OSU, ODA, local and regional extension offices. It is a slow death by many cuts. Again, will we still have a coordinated army of specialists to deal with SWD?

Secondly, will the ODA, dealing with other states, be able to keep Oregon’s myriad of horticulture crops moving, both nationally and internationally? It is difficult enough to battle an invasive insect when the potential damage is more limited. But, this pest attacks, from the various descriptions, across the range of berries and fruit. I am trying to find out if they like tomatoes. As a grower, this would change my tried and true systems.

Which leads to a third question…what do the organic growers do?
Conventional growers have a list of weapons that will work. But, it still adds to their projected costs which with most crops would impact bottom lines. Organic growers do not know enough yet to identify even a control possibility. They need to know if “fruit” might later include not only tomatoes, but many varieties…peppers, eggplant, squash. Any organic option will require many applications and this pest is prolific…10 generations a summer, over 100 eggs per female…you do the numbers.

Once all the crops in danger are indentified, then strategies can be developed. In some cases, I may go for a literal cover strategy…closed hoop houses, possibly enclosing with row crop floating covers. But this is a very tiny fly, so there is question what will keep them away?

Meanwhile, this type of challenge seems to support the idea of more diversity in the growing of many crops; and more smaller, local producers serving surrounding communities. This lessens the opportunity for pests moving into vital food chains. I mean, Oregon’s blueberry fields and peach orchards must have looked like SWD nirvana…”here’s a neighborhood we can settle in.”

At this point it’s more questions and a scramble for information. Stay tuned.