By Peter Heffelfinger
Posted June 8, 2020
A new backyard pest
I spent several days this week dealing with an infestation of what looked like tiny, black, leaf-eating caterpillars that swarmed over a mature stand of highbush cranberry shrubs and also onto one nearby snowball bush. The leaves were skeletonized, leaving the stems and veins intact, by what resembled tiny leeches with legs, crawling up the main trunks to get to the foliage. The only solution was to cut down the tall shrubs completely and take them to the burn pile for immediate incineration. I am hoping I got rid of enough of the pests before they invade a nearby prized Japanese maple or a Korean dogwood that is in full bloom.
The soft cranberry shrub leaves were more susceptible than the thicker leaves on an adjacent shiny laurel, which was also covered by what looked like sticky frass, the technical term for insect droppings. So the laurel went as well, just to be safe. The recent heavy rains and lush undergrowth may have been part of the cause, but it is the first time I have seen such an invasion on mature shrubs that I have been growing and pruning for several decades. It certainly felt like an outbreak that had to be dealt with firmly. I will be on the lookout for further signs and will try to identify the critters specifically.
As the tomatoes climb up their supports and start to flower, it is important to remember that in order to set fruit the plants need to be kept above 50F degrees at night. When closing up the hoop house in the evening to maintain the heat, I give the tomato cages a quick shake to get the pollen out into into the air. Hopefully the small green buttons of nascent tomatoes will soon start to appear. The cherry tomatoes always come first, given their small size, leading the way for the larger standard varieties.
Vegetable perennials: artichokes and asparagus
I grow a bed of the standard Green Globe artichokes, which are just coming on. They are a welcome treat, but somewhat bland-tasting, and must be picked before they get too tough. I do have one bush of purple artichokes, Violetta de Provence, an Italian variety that produces smaller chokes, but with a much more delicate flavor. When picked early, you can eat almost the entire bud. Gourmet thistles.
The other garden perennial is the bed of asparagus, which is just reaching maturity in its third season. It has been worth the wait. Now one can pick a high percentage of the stalks, which are decidedly sweet when eaten straight from the garden. A key to a sustained harvest is to keep the bed well watered as the roots send up the shoots.
The first rush of ripe broccoli is also here, having recently emerged from their floating row cover. I blanch the flowerets for a few minutes just until they turn bright green, then quickly chill in cold water. I like them as an appetizer dipped into a sauce of mayonnaise mixed with a bit of dry mustard and a spritz of lemon juice. I have also found that the plain stems can be eaten as well if you cut them into small slices or julienned strips and blanch them a bit longer than the tops before chilling. If the stem is particularly tough, use a vegetable peeler to get rid of the thick skin. Eat the whole vegetable.
I experienced this last year on my beloved Japanese Snowball bush. The leaves were decimated by these larva so I
had to cut it down to the trunk. Unfortunately, they returned this year, all over the new growth. The cranberry bush in my neighbors yard was the first I had noticed last year, they are both in the viburnum family. It doesn’t look like there is much hope without chemicals! So sad!
The pest damaging Peter’s leaves is probably the viburnum leaf beetle larvae, due to the nature of the skeletonizing of the leaves.
Unfortunately he did not take a picture of the actual critter itself!
It is wise when you first see damage to take a close-up picture for i.d. and then start picking off the insect larvae themselves. If they are too numerous on a leaf just take off the entire leaf to keep them from proliferating. Place in paper bag and crush. There may be another hatch in July. A healthy plant will put out new leaves, but the plant cannot usually withstand too many years of this.
I’m attaching a link to information about this pest from Hortsense: http://hortsense.cahnrs.wsu.edu/Search/MainMenuWithFactSheet.aspx?CategoryId=1&SubCatId=4&PlantDefId=38&ProblemId=767
Non-chemical action is preferred to protect our beneficial insects out there now.
Thanks for the information, I would never use chemicals on anything!
Asparagus – ugh. When I was a little tyke in Michigan there was essentially a wild asparagus field behind our house. We ate a lot of asparagus and we kids grew to hate it. However, Mom would make 10 or 12 bundles of fresh-cut tender asparagus and my older sister and I would traipse up and down the roads in our area at about 4 pm and sell it for $0.15 / bunch. We sold it to every house we visited – usually three times a week! Kept us in candy bars and mom in sugar!!!
Three years ago, I also found small black leech-like insects on what remained of my decimated snowball and cranberry bushes! I chose a warm day to methodically wash them off each leaf (who knew they had so many!) with a gentle spray from a hose. Last year I had no problem – the bushes were fine with no insects. This year, they are back on one snowball. I did the same water treatment again this year, and they have been gone for a few weeks now. I expect them to stay gone as the new growth appears. No chemicals needed, just some messy time.