- Author: Alison Collin
This year appears to have produced a bumper population of Black Widow (Latrodectus) spiders. Having had too many close calls with these arachnids, I decided to eliminate as many as possible before I became a victim. I have no problems with other spiders and welcome them in the garden, appreciating their effect on the insect population and delighting in the beauty of a perfectly formed Orb spider's web. However, this summer it seemed that almost everything I touched had a Black Widow lurking underneath; when I filled my watering can one came out of the top as the water level rose, when I harvested my squash there was a large one under one of the fruits, the children's tree house had them in the corners, and as I was fitting a child's car seat into my car one emerged from under the seat as I tightened the final strap. Enough! I had to take action.
The first thing was to find out as much as possible about the habits and life cycles of the Black Widow, and the IPM website http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74149.html was invaluable for this. It shows photographs of not only adult female Widows with their shiny, black round bodies with the red hourglass markings on their lower abdomen, but also the male and immature forms, both of which look very different. Fortunately, these spiders are shy and tend to retreat to a hole or crevice if disturbed. This very habit means that the unwary may accidently disturb them and induce a bite – often by putting shoes on that have been left outside or by picking up such things as logs or pots that have one underneath. Their bite contains a neurotoxin which induces symptoms such as a localized rash, severe muscle cramps, possible paralysis of the diaphragm, nausea, vomiting, and changes in vision. Anyone bitten should use an ice-pack on the bitten area and then seek immediate medical help, if possible taking the culprit with them to confirm identification.
Black Widow spiders like to live in undisturbed clutter around homes and seem equally at home underneath garbage cans, under the covers of irrigation set-ups, in wood piles, in natural stone facing of retaining walls and houses, or in seldom-used children's' plastic toys where they build webs in the wheels and under seats. They are common in the darker corners of garages and sheds and will occasionally be found in similar spots inside homes. Their webs are not what we think of as the classic spider's web but rather a disorganized collection of very strong threads, often with bits of leaves or dead grass hanging in them and frequently containing small and very tough egg sacs which may contain up to three hundred eggs. The female can produce up to 10 of these from one mating! On average, they live for about three years. The population of these spiders is only maintained if there is enough food for them. It is not likely that there will be a shortage, since they will eat any insect: beetles, crickets, cockroaches and even scorpions.
I wanted to gain some control without the use of chemical sprays. I identified various webs, but as soon as I approached, the spiders would take cover in some inaccessible spot. Then a neighbor suggested that I go out after dark with a flashlight so, armed with an old shoe, I chose a warm moonlit night to begin my “Widow Vendetta”. I could not believe just how many spiders there were! On a raised planter bed with concrete stone edges, there was a large adult female about every 18 inches around the whole circumference. They were sitting in their webs upside down with their red hourglass markings clearly visible and they did not scuttle away when I shone the light on them, making a quick dispatch an easy matter. I then concentrated around the house foundations where there were dozens of tiny spiderlings setting up home. The flashlight had the benefit of casting their shadow onto the concrete path which made their exact position easier to see, and I often killed 30 spiders in one night. (I am relieved that this eccentric behavior has so far not appeared in the local “Police Blotter”)! I followed this routine every couple of weeks throughout the summer and swept the walls with a flat broom afterwards, which made it easier to spot new webs as they appeared. I have pruned vegetation back from beside the house and have tried to limit storage of items near entrances. A pressure jet of water could be used to dislodge some from more difficult positions, although that would surely be an egregious use of such a precious commodity during a drought.
Praying Mantises are particularly fond of these spiders, and some wasps parasitize them, so I am hoping that due to our combined efforts, we will gain some control. Meanwhile, I have been wearing gloves when performing gardening tasks, and have been carefully checking and brushing logs and plant pots before bringing them into the house. Only time will tell whether my efforts will make a noticeable difference to the Black Widow population, or whether I have upset the natural balance enabling some other noxious species to take hold instead.
For more info on Black Widows, see: http://www.livescience.com/39919-black-widow-spiders.html
- Author: Harold McDonald
A gardener struggling to use mountains of zucchini is almost a meme in the gardening community, so it's very humbling to have to tell people you can't grow it—kinda makes you look like a grade down from a Master Gardener! And even though I know my conditions are extreme out here at the edge of the Volcanic Tableland, my pests normally come on four legs, not six. So, having to surrender growing squash to the bugs that stole their name is pretty frustrating. But I know this is a situation that many better gardeners than I have surrendered to!
The normally-more-than-daily examinations of each giant, sticky, rippy leaf for the glistening little bronze eggs, all while the progenitors scurry for safety in the folds of the struggling squash plant is just more than most of us are up for.
I know people have lots of strategies to deal with these pernicious pests, but none that have ever seemed worth the work to me. All require diligence. Leaving home for even a few days can throw momentum back to the bugs. More than that and the situation could get completely out of control!
But gardeners are always dreamers, and long before the days warm up in the spring, we are scheming, trying to solve seemingly unsolvable problems—at least I am—and squash bugs is a tough one. I started searching online, but again, the solutions weren't easy, realistic, or convincing.
Somehow, while researching squash I stumbled on parthenocarpy, a term I had learned somewhere back in a plant class, but certainly not a term I would have known to search for. Seedless watermelons are parthenocarpic—production of the fruit does not require fertilization of the ovule. For more about parthenocarpy and cucurbit sex, see this University of Nebraska pdf.here.
The important thing is that since fertilization is not required, you can keep the plants under floating row covers for their entire lives, physically protecting them from squash bugs. If you're inexperienced with row covers, they can really help in a number of situations, probably more commonly to raise temperatures in the shoulder seasons. Here's an introductory article on row covers from a MG blog in Wisconsin.
Yeah, but where do I find seeds? If they're parthenocarpic, do they even have seeds? Yes, they do have seeds, and some of the top varieties are ‘Cavilli,' ‘Venus,‘ and ‘Gold Rush.' I chose ‘Partenon'*—who can resist a squash that seems to have been named after a Greek temple? I planted the seeds in the ground in late May without a clear plan of exactly how I would cover the plants. But they did indeed come up. I improvised something from bits and pieces I had laying around, and eventually built a more robust but very simple portable hoop house (rebar and PVC) for them.
The results have been beyond what I could have imagined. So far, no squash bugs and plenty of zucchini! I'll do this again next year in a different part of the garden. I may look for an additional parthenocarpic variety. This field test from Cornell ranks ‘Dunja' as even more efficient than ‘Partenon.'
But with success, I'm now the one searching my cookbooks, Paprika (an excellent recipe database program for your digital devices) and online for good ways to use the bounty. Today I made zucchini pickles and a fabulous zucchini butter that will go great on crackers or bread, perhaps with a bit of pesto or fresh basil on top and—with any luck—tomatoes later in the season!
*By the way, in the University of Nebraska presentation, they refer to ‘Parthenon' zucchini from Thompson and Morgan. It is actually ‘Partenon'—no h in there!