Gardening with Xpress: Tips for quashing squash plant pests

Your harvest baskets are probably overflowing, just like the insect populations in your gardens. Maybe you’ve begun planting for fall, too. As you keep tending the garden, be sure to send your questions to me at gardening@mountainx.com.

Outsmarting squash pests

I had a beautiful patch of buttercup squash that was doing great, then one day I checked on them and they were all dead. What happened?

Oh, the drama and tragedy of engaging with the living world! Although I can’t say for sure without more information, the most likely culprit is the squash vine borer (Melittia cucurbitae), an orange and black moth that is active in the daytime. They deposit their eggs on the stems of squash plants and the resulting caterpillars bore into the plants, quickly killing them. If you look at the base of the stems of your plants, it’s likely you’ll see big wounds with bits of chewed-up squash stem around their edges. The fat white caterpillars with black heads may or may not still be present.

Unfortunately, once damage has occurred, it’s very difficult to treat this pest. That’s because by the time you notice the plant suffering, vine borers have already entered the stems and begun consuming them from the inside out. In rare cases  you can save the plants by surgically opening the stem with a sharp knife and piercing the caterpillars, or injecting Bacillus thuringiensis — an organic pesticide made from a bacterium, also known as Bt  — into the stem. This will only work if the damage hasn’t gone too far and if you’re able to kill all the caterpillars who may be hiding deep inside the stems.

The best way to approach this pest is through prevention. One way to do this is to cover squash plants with floating row cover until they flower. Depending on how many plants you have, this may or may not be practical. Another option is to wrap aluminum foil around the base of each plant once it has emerged (or right after transplanting, if you go that route). This can prevent vine borer caterpillars from burrowing into the stems, though it’s still a good idea to monitor the plants for eggs (which are dark brown and round), so that you can act fast if some end up emerging and making their way past the physical barrier of the aluminum foil.

There are three main species of winter squash that we home gardeners tend to grow: Cucurbita maxima, C. pepo and C. moschata. Within these species there are dozens and dozens of varieties. The difference between a species and a variety is that plants in different species cannot interbreed, whereas different varieties, if they’re in the same species, can cross with each other.

The maxima group includes your buttercups, along with candy roasters, red kuris, kabochas, hubbards and others. Unfortunately, this species seems to be the most susceptible to vine borers, along with other pests and diseases. The pepo group includes most zucchinis and summer squash, along with delicatas, acorns, true pumpkins and others. This group is moderately susceptible to borers, too.

Finally, the moschata species, which includes butternuts, cheese pumpkins and others, seems to have the most resistance to vine borers, as well as other pests and diseases. No species or variety is immune to these or any pests, but planting a variety from the moschata species, along with taking the preventive measures I mentioned above, will give you the highest chance of success.

What to do with all the zucchini

I have so many zucchinis, and I’m getting tired of eating them. What are your favorite ways to prepare and preserve them?

Oh, the abundance of high summer; what a mixed blessing. Yes, zucchini and other summer squash can be impressively productive, and with their mild flavor and sometimes watery texture, it’s easy to get tired of incorporating them into every meal. One key to enjoying zucchinis is to harvest them while they’re young, before the skin gets tough and the seeds form. Both their flavor and texture are much better when they’re small, and picking smaller fruits means that you may not feel so totally inundated. Another cardinal rule is to cook them enough, but not too much. Both overcooked and undercooked zucchini is much less delicious than when it’s perfectly toothsome.

My personal favorite ways to eat zucchini and summer squash include: marinating and grilling strips, adding them into curries and stir fries, zucchini fritters, zucchini bread and créma de calabacín soup (check out a recipe at avl.mx/dyh). I usually use a combination of olive oil, garlic, garden herbs, red wine vinegar and a dash of honey and tamari for the marinade when I’m grilling zukes. Restaurateur and cookbook author Yotam Ottolenghi delights at getting creative with fresh ingredients and shares many delicious zucchini-focused recipes in his cookbook Simple. Another one of my favorite vegetable-loving chefs, Deborah Madison, includes zucchini and most veggies you may be growing in her various fabulous books and especially in Vegetable Literacy.

As far as preserving zucchinis, a wise friend and fellow large-scale gardener inspired me to make and freeze zucchini bread, rather than shredded zucchini. As they said, it’s just as easy to make a bunch of batches of bread when the zucchini is fresh, and it’s way more exciting to pull a ready-to-eat loaf of zucchini bread out of the freezer, rather than a ziplock plastic bag of zucchini. We’ve both found ourselves with freezers full of such bags come the following summer, which defeats the purpose of preserving!

I’ve had some success with zucchini pickles but only when they’re picked very young and therefore stay firm through the pickling process. I like to use a Mexican-inspired spice blend for these (cumin, Mexican oregano, allspice, garlic, chilis, etc.) and then eat them as a taco topping.

Cover crops without tilling

I’d like to plant some cover crops, but I also want to do no-till gardening. Can the two practices coexist?

Cover cropping and no-till gardening can absolutely coexist. In fact, they work really well together. Instead of chopping up and mixing the bodies of cover crops into the soil, you’ll end up laying them down in place as mulch or raking them away to use as mulch elsewhere.

With all cover cropping, choosing the right varieties to plant at the right time, then killing, or “terminating,” them at the right stage of their growth are the most important factors. (You can find an information sheet on cover crops for different seasons from the Sustainable Agriculture Research and Education organization at avl.mx/dyi.) In most cases, it’s ideal to terminate cover crops when they’re flowering. This means that some of their energy is still down in their roots, where dieback will nourish soil life, and that the likelihood of regrowing will be lower because they’ve switched gears from growing into flowering.

You can mow with a scythe or hand sickle to terminate cover crops, or you can crimp them down with a metal T-post, board or other method. After that, you may want to smother them with a thick layer of mulch or a UV-stabilized plastic sheet such as a woven weed fabric or silage tarp.

One tricky part of using cover crops with no-till gardening is that you won’t be able to direct-sow small-seeded crops right where a cover crop was. Instead, plan to transplant, sow something with big seeds or wait for the cover crop plants to completely decompose.