Among its many valuable attributes, our digital world also has the capacity to whip people into a froth, goading us into action, reaction and downright hysteria. The cicada has all the primeval panoply to feed this panic, with its orange-veined wings, black body, beady red eyes and sheer size. It is a big, noisy, pulsating bug, and there will be gazillions of them. We could run for the hills, but the hills will have them, too.
Better, perhaps, to inject some rationality into the event, especially as the Brood X cicada relates to our yards and gardens.
The insect may disrupt things in May and June — especially June — but its destructive capabilities are limited. The female makes a slit along branches to lay eggs. With sufficient egg-laying, the branches will die and droop by summer’s end. On established trees, this is a merely cosmetic issue. On baby trees, there is a greater risk of disfigurement and even death caused by this damage, but that is not common or guaranteed.
What is more important is what the cicada does not do. It does not bite or sting us, it is not poisonous to the touch, and it does not eat our plants, or give them disease, or cover our patios and outdoor furniture in foul secretions.
The brown husks of the nymph casings pile up in May, and by July, the garden may be littered with dead cicadas, but these can be incorporated into the compost pile.
Cicadas tend to congregate in wooded areas, because their life cycle depends on tree branches for egg-laying and on tree roots to sustain the burrowing nymphs after they hatch and fall to the ground. So, if you live in a neighborhood that was a field in 2004, or that has few trees, you may see little cicada activity.
Over the next month, you may find animals scratching the soil to find and eat nymphs. These include foxes, raccoons, possums, skunks and even squirrels. Such scratching might mess up beds or lawns, but the damage will probably be localized — and is easily fixed. There’s not much you can or should do about it.
The fertilized female cuts longitudinal slices on the underside of branches, preferring stems that are approximately ¼ to ½ inch in diameter. That includes a lot of trees and shrubs, particularly young ones, but on mature trees and shrubs, this branch harm is little more than a summer pruning.
Damaged branches can be removed, promoting bushier regrowth and minimizing the slight chance of disease entering the wounds. Don’t risk your neck on a ladder; the damage will vanish in due course. On inaccessible branch tips high in shade trees, the brown, flagging foliage will be forgotten come the fall leaf drop.
Young trees planted in the past couple of years may benefit from protective netting. Garden centers and online retailers have stocked up in advance of the phenomenon. If you want to net a small tree, here are some key considerations:
●Netting should have holes no larger than half an inch. Standard one-inch bird netting won’t exclude cicadas.
●Make sure there are no active bird nests before you net.
●The seams of the net must be securely fastened to avoid gaps. Cable ties are useful. Two pairs of hands are better than one.
●Birds and snakes can get caught in netting, especially baggy netting.
●Do not net now. Wait until you start to see cicadas emerge from the soil — around mid- to late May — and take the netting off promptly after the females have finished laying eggs and died, about six weeks later. May is a month of rapid plant growth, and netting early may constrict and distort this annual spurt, according to Stanton Gill, a University of Maryland extension specialist.
●Coverings with fine mesh or the spun fabric of vegetable row covers will impede air circulation and may promote fungal diseases, Gill said.
●Avoid overhead power lines.
About the most uncool thing you could do is try to eradicate the cicadas with insecticides. There will be so many transient cicadas over a month or more that you would have to continually reach for the sprayer. Birds, pets and other animals may well ingest the poisons when they eat targeted cicadas. In addition, you would be killing countless numbers of other insects, including bees and butterflies.
One study has shown that most contact insecticides do not significantly reduce branch damage, especially when compared with netting. Another study, by entomologists at the University of Maryland, demonstrated that a systemic insecticide named imidacloprid did reduce egg-laying, but again, netting was more effective. Also, imidacloprid and other neonicotinoids are highly controversial pesticides because of their toxicity to beneficial pollinators, including honeybees.
Organic sprays applied on branches to discourage egg-laying have little value, according to one study. Neither kaolin clay nor a mix of neem and karanja oil significantly reduced damage on young apple trees, researchers reported in the Journal of Entomological Science.
In another study, researchers found that certain trees and shrubs were more prone to damage, including the oak, maple, mountain ash, ornamental cherry, hawthorn and rose, though the cicada is drawn to a wide array of native and nonnative woody plants. They also found that some woody plants healed faster than others — willow, dogwood and forsythia, for example — but nearly all of the 17 genera studied were almost fully healed after two growing seasons. The damage on redbud, walnut and basswood took longer to heal.
The point is, cicada damage is rarely fatal or lasting, and the most prone plants — young trees — are easily netted. In one respect, the insect is saving you the bother of aerating your lawn and woodland beds. The nymph tunnels open the soil to air and water — all to the good, though an extensively tunneled area might benefit from watering to prevent exposed roots from drying out.
If you have a small garden pond, you may want to place a net over it, or be ready to scoop out drowning cicadas as the mood takes you.
And get some earplugs as a buffer to the cacophony of the male cicada, which seeks to draw a mate with a chirping that can reach more than 100 decibels. Amid all these practical considerations, don’t forget to ponder the miracle of the cicada’s long absence followed by its moment in the sun.
A short film by Samuel Orr, “Return of the Cicadas,” captures this magic masterfully.
Tip of the Week
In gardens with vertical supports or mesh fencing, cherry and grape tomato varieties are vigorous, require little care beyond tying as they grow, and produce fruit for months. Popular varieties include Super Sweet 100, Black Cherry, Sungold and Red Currant. They can still be started from seed for May planting.
— Adrian Higgins
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