We're beginning to think we're not meant to grow our own cucumbers and squash. Any advice for keeping little striped and spotted beetles from devouring all the leaves, and squash bugs from sucking them dry? We're growing organic, so tell us what we can do without standard pesticides. - C.C. -
In organic gardening, being there is not half the battle, it's the whole thing. Check the plants often and you can probably stay ahead of this game with manual controls.
We think our approach is in line with most others who grow organically and done time in beetle battle or on a squash squad. To garner any new tactics out there, we've also created a place for others to add those suggestions, too. Keep an eye on that spot in the Forum.
Right now, inspect the leaves, especially the undersides. Scrunch the bugs -- wear gloves to avoid acquiring their stink -- and smash their eggs. Alternatively, collect the eggs you find and put them on a dish at your bird feeder. It's very satisfying to watch goldfinches and chickadees scarf bug eggs.
Squash bug eggs are in groups up to 20, tan to yellow, darkening as they age. They hatch in about a week, so patrol thoroughly at least once a week to undo the efforts of the first group of squash bugs. Cut that batch short and you avoid the hordes that can come from Generation Two a month later.
Alternatively, or in addition, clear the mulch away from the bases of the vines so there are less hiding spaces, and apply pyrethrum or diatomaceous earth -- powder from shells of very tiny marine crustaceans, a dust that kills soft bodied insects via desiccation. (The insecticide pyrethrin is allowed in most organic programs. It is derived from Pyrethrum/painted daisy flowers.)
Then as harvest ends, clean up very well around the garden to reduce hiding places for overwintering bugs. Burn or hot compost all plant debris. Scrape and store wooden accessories dry and well above ground. Hoe or till at least once in late fall to expose any adults that burrowed in.
Next year, grow bug-resistant squash and cukes, if these choices suit your use: Blue Hubbard squash, Ashley or Gemini cucumbers, etc.
There is plenty of great advice available in Extension bulletins, especially if you use technical terms as you search and apply an "Images" filter. For instance, here is this very practical, well illustrated publication from Colorado State University Extension.
Leaves with pale or wilted spots, and sunken holes? Squash bugs have been at work. Ragged holes chewed in the leaves? Stem bases scraped? Cucumber beetles. Both pests have been at work here.
These are tougher to control because they lay their eggs in crevices in the soil around the base of the plant. While the scraping, chewing damage the adults do is infuriating, it may be the gnawing on roots and stem base that the grubs do, that does more harm.
Note: Information about cucumber beetle eggs and squash bug eggs has become tangled, in books, on the Internet, even in Extension publications. Ignore references to beetle eggs laid on leaves. Once in a while you might find striped cucumber beetle eggs in groups of 20+ on ground level leaves but most of the time they deposit those eggs in the ground. Spotted cucumber beetles lay eggs around the base of other plants, not the cucurbits. Their alternate hosts include corn, peas, potatoes, grass and quite a few others.
Track and squish the beetles every time you're in your garden. Make those visits frequent during June. Be glad if you're in the northern U.S., as we are, because we have just one egg-laying generation per year to hunt down.
It was probably cucumber beetles that scarred this stem base. Look where the arrow points and you can probably see two eggs there, too.
Having had cucumber beetles once, expect them the next year, as early as the soil is warm enough to set out cucumber plants. The overwintered adults will come to those new plants to lay eggs, so cover your transplants or seeded rows with floating row cover and leave them covered until flowering time when you will have to open them to pollinators for at least a few hours a day. Fortunately by then most of the cucumber beetles will have done their egg laying and your plants won't suffer grub chewed roots and stem bases.
In case it irks you to hear this called a "game:" We're not being flippant, only practical. It's a grim humor with which we entertain ourselves, in bug crunching much as we do in weeding. We joke as we hunt, and compete with ourselves and each other for total killed. "Take that you devil!" "Ah ha, two at once!" Etc.
If there are children about, we're not above hiring them as accomplices if they're old enough to hunt without crashing about in the plants. We pay per bug! Like you, we spend a lot of time and not a little money on seed, plants, plant protection and accessories, so we aim to harvest.
Also, we hunt information as well as pests. In that we've learned to look for a pest's scientific name (whether fungus or beetle, it has an official name). Once we have it, we use that in Internet- and reference book searches. Wit that key, we can often cut straight to information from the most qualified sources.
Squash bug: Anasa tristis
Striped cucumber beetle: Acalymma vittata
Spotted cucumber beetle: Diabrotica undecimpunctata howardi