PEST PLANS
My Sweet, Corn
Spring is here this week, weatherwise, at least. Not to bring back bad memories, but with real spring just around the corner, now is a good time to revisit two or three of last year’s worst pest problems, and plan some sort of counteraction. Not that those memories are really that bad; the interaction of pests, plants, the environment, and my hopefully green thumb is always interesting.
The most serious pest problem last year, most serious because it affected one of my favorite vegetables, was a disease that devastated my later plantings of corn. Looking at the symptoms — yellow streaks on leaves that turned to tan, dead areas — my diagnosis was the bacterial disease, Stewart’s wilt. Some plant pathologists pointed out that Stewart’s wilt is very rare around here, and that the problem was probably the fungal disease, northern corn leaf blight.
Disease development on leaves
I’m not 100% convinced it’s the blight but, more important is what to do in either case. I like my sweet corn. (Popcorn and polenta corn were unaffected.) Stewart’s wilt can be avoided by growing resistant varieties. But not only do I like my sweet corn; I like specifically Golden Bantam sweet corn.
A hundred years ago, Golden Bantam corn was bred into a number of hybrid varieties, some of which are resistant to Stewart’s wilt. Golden Cross Bantam, for example. As I said, though, I like my Golden Bantam. I’ve grown Golden Cross Bantam and its flavor fell short of Golden Bantam.
Northern Corn Leaf Blight
As a nonhybrid variety, Golden Bantam turns up in a number of strains. My seed came from a few sources, and it’s possible that some strains are more resistant than others. My two earlier ripening beds had no disease. Last year I didn’t keep records of which beds got seed from which sources. This year I’ll record it.
Northern corn leaf blight can also be controlled with resistant varieties. As I wrote, though, Golden Bantam is the variety for me, so other varieties are not an option, for now at least.
Plus, there are other options for dealing with northern corn leaf blight. Thorough cleanup at season’s end removes spores that would overwinter. Done. Not planting corn in the same bed for one to two years to starve out the disease. Done. Good air circulation and humidity control by keeping weeds in check. Not so done each year. Colder, damper air descends readily into the Wallkilll River Valley here and, while weeds are under control, I do a lot of interplanting, which has the same effect, humidity-wise, as weeds.
Who knows? Another season, different conditions. The problem, whichever it is, never showed up before; perhaps it won’t ever again.
An Unwelcome Newcomer
The other significant pest problems last year were with my onions and leeks. As usual, I started onions from seed indoors in February and planted them out in early May. Another batch got direct seeded right out in the garden in April. Both plantings — I’m ashamed to admit — yielded stunted bulbs, many no bigger than a nickel. Leeks likewise were stunted, or deformed.
Also embarrassing is that I didn’t take the trouble to examine the plants closely for clues. This would have been relatively easy since the probable culprits were leek moth or thrips, both now common, around here, at least. Plus, I’ve previously had a problem with leek moth.
Leek moth, a European native, is a relative newcomer on this side of the Atlantic, first showing up in northern New York state in 2009. Temperatures above 50°F in late winter awaken papae or adults overwintering in debris, and Ms. Leek Moth soon starts laying eggs, lots of them. In less than a month, new adults start feeding on leaves. Subsequent generations follow suit, feeding on leaves, weakening the plant, and also the parts — stalks and bulbs — that we want to eat.
Early signs of impending damage are the eggs, tiny and transluscent and laid on the undersides of the leaves. Or, later, the caterpillars, slender, yellow and also small, less than one-half inch long. The important thing is to take action at the first signs of damage — holes in leaves and caterpillars. To see the caterpillars, leaves of garlic and leeks need to be unfolded; hollow leaves of onions need to be opened for an inside look.
Leek moth damage, later
Preemptive action would be to use a lightweight floating row cover beginning early in the season to keep Ms. Leek Moth from laying eggs on plants.
Once damage or caterpillars is found, spraying, my least favorite garden activity, is needed. Organic sprays include Pyganic, which is effective for a couple of days, or, more lasting, Entrust, a natural substance made by a soil bacterium. In either case sprays need to be applied strictly according to label directions, both for effectiveness and for legality
Thrip, Thrip, Thrip – No, Not a Frog
Thrips, the other possible, or additional, culprits are very small, but their damage is telling: silver lines and/or small white patches on leaves and tip dieback. To see the culprits themselves, you’ve got to look closely between the leaf folds, zeroing in on the youngest leaves, for light yellow nymphs and darker adults. Hot, dry weather suits them best, which were the conditions here last summer.
Thrip damage
Because thrips overwinter in debris, thorough cleanup helps. Straw mulch has potential, although one study showed that while it reduced the number of thrips, it didn’t affect yield. It did increase the number of jumbo onions, though. Go figure.
Certain kinds of onions are more resistant to thrips than others. In general, red onions (which I anyway don’t grow) are very susceptible, yellow ones (which I do grow) less so, and Sweet Spanish onions (which I have grown in the past) are relatively resistant. I’ll no longer grow the variety Candy, which is listed as susceptible.
Certain plants, on which thrips do little damage, can draw thrips away from the onions. Carrots, tomatoes, cabbage and its kin, carnations, and chrysanthemums, as examples.
And, of course, there are organic sprays, a last resort for me. Beauvaria, a naturally-occuring insect killer, for one. Also the relatively benign insecticidal soap paired with Neem. And again, Entrust.
As I said, I’m not bemoaning these insect and disease pests. It’s reassuring for me to stop and think how few or no pest problems vegetables typically affect my kale, tomatoes, peppers, okra, and most other vegetables grow. They all grow well with little more than yearly additions of compost to the beds, and timely planting and watering.
Prune Fearlessly
A reminder that I’ll be holding a FEARLESS PRUNING webinar on March 29, 2021 from 7-8:30pm EST. This webinar will take the mystery out of pruning, so that you can prune your lilac and rose bushes, apple trees, blueberry shrubs — all trees and shrubs, in fact — to look their best and be in vibrant health. Fearlessly. For more information and to register, go to www.leereich.com/workshops.
FEARLESS PRUNING
FEARLESS PRUNING WORKSHOP/WEBINAR
A workshop/webinar to take the mystery out of pruning, so that lilac and rose bushes, apple trees, blueberry shrubs — all trees and shrubs, in fact — can be pruned to look their best and be in vibrant health. Fearlessly.
Topics will include:
•Why prune?
•Tools for pruning.
•How plants respond to various kinds and timing of pruning.
•Details for pruning flowering shrubs, trees, evergreens, and fruit plants.
•And a fun finale on creating an easy fruiting espalier. (Don’t know what espalier is? You’ll learn it at the webinar.)
And, of course, there will be time for your questions.
Date: March 29, 2021
Time: 7-8:30 pm EST
Cost: $35
Registration Link
https://us02web.zoom.us/webinar/register/WN_RfkO-_nJT8S-LximcfG24Q
After registering, you will receive a confirmation email containing information about joining the webinar.
HOW ABOUT THOSE OLD SEED PACKETS?
It’s wasted effort to sprinkle dead seeds into furrows either in the garden or seed flats. Seeds are living, albeit dormant, embryonic plants which do not live forever.
When you buy a packet of seeds, you’re assured of their viability. Government standards set the minimum percentage of seeds that must germinate for each type of seed. The packing date and the germination percentage often are stamped on the packet. (The germination percentage must be indicated only if it is below standard.) I write the year on any seed packets on which the date is not stamped.
Your old, dog-eared seed packets may or may not be worth using this season. It depends on where the packets were kept and the types of seeds they contain. Last year I got tired of trying to decide how well my seeds were stored and which were still worth sowing; I took action.
Anti-Aging Treatments
Conditions that slow biological and chemical reactions also slow aging of seeds, i.e. low temperature, low humidity, and low oxygen. In years past, I’ve stored seeds in canning jars in my freezer, then moved the jars to the refrigerator as the freezer filled in fall. Powdered milk sprinkled into the bottom of the jars maintained low humidity. (Or so I assumed.) But all those jars took up lots of space, especially as my seed collections grew, and seed packets don’t pack well into canning jars.
As far as low oxygen storage, it’s not practical for most of us. I did try, one year, to create low oxygen seed storage by reversing gaskets and putting a one way valve on a bicycle pump. 
This allowed me to draw some of the air out of the jars with a tube connecting the pump to a ‘FoodSaver Wide-Mouth Jar Sealer.’ It did (usually) create somewhat of a vacuum but it was too much trouble to get at the seeds and re-seal a jar each time. And, again, seed packets don’t pack well into canning jars.
So last year I came up with a figurative “better mousetrap.” After much searching for a plastic, freezer-safe, air-tight, leak-proof, reasonably-sized tub for the bulk of my seeds — a stout order, all this — I came upon the ‘Komax Biokips 35-Cup Large Food Storage Container.’ Perfect!
I measured, cut, and hot-glued a piece of 1/4-inch plywood to run up the center of the tub to allow for two rows of seed packet. A couple of 100 gram silica gel packets in the tub at the end of each row keeps humidity low. The packets are easily rejuvenated in a warm oven for 20 minutes. I just measured the humidity in the tub (I like to measure); it’s a dry 17%.
Moving the tub into the relative coolness of my basement in summer should maintain conditions in line with the guideline for seed storage that Fahrenheit temperature plus relative humidity should total less than 100. Come cooler weather in fall and then cold weather in winter, back the the tub goes to a shelf in my unheated workshop.
Worth Saving?
Seeds differ in how long they remain viable. Even with the best storage conditions, it’s not worth the risk to sow parsnip or salsify seeds after they are more than one year old. Two years of sowings can be expected from packets of carrot, onion, and sweet corn seed; three years from peas and beans, peppers, radishes, and beets; and four or five years from cabbage, broccoli, brussels sprouts, cucumbers, melons, and lettuce.
Among flower seeds, the shortest-lived are delphiniums, aster, candytuft, and phlox. Packets of alyssum, Shasta daisy, calendula, sweet peas, poppies, and marigold can be re-used for five or ten years before their seeds get too old.
In a frugal mood, I might do a germination test to definitively measure whether an old seed packet is worth saving. Counting out at least 20 seeds from each packet to be tested, I spread the seeds between two moist paper towels on a plate. Inverting another plate over the first plate seals in moisture and then the whole setup goes where the temperature is warm, around 75 degrees. After one to two weeks, I peel apart the paper towels and count the number of seeds with little white root “tails”.
I figure the percentage, and if it’s low, the seed packet gets tossed into the compost pile (not given away!). Or, I might use the seed and adjust my sowing rate accordingly.
And the Record Is . . .
Among the shortest-lived seeds are those of alpine plants; their viability might plummet after only a couple of weeks.
As far as longest-lived seeds, there’s the story of the 10,000 year old lupine seed that germinated after being taken out of a lemming burrow in the Yukon permafrost. Alas, it’s only a story, one debunked by radiocarbon dating.
The true record for seed longevity was, until recently, 2,000 years, and was held by a date palm grown from seed recovered from an ancient fortress in Israel.
No one knows exactly what happens within a seed to make it lose its viability. Besides lack of germination, old seeds undergo a slight change of color, lose their lustre, and show decreased resistance to fungal infections. There’s more leakage of substances from dead seeds than from young, fresh seeds, so perhaps aging influences the integrity of the cell membranes. Or, since old seeds are less metabolically active than young seeds, the old seeds leak metabolites that they cannot use.
(The above was adapted from my book The Ever Curious Gardener: Using a Little Natural Science for a Much Better Garden available from the usual sources and, signed, from me.)
