In the realm of garden and landscape pests, there is good news and bad news. For those of us who have witnessed severe defoliation of trees, shrubs, and even some herbaceous plants, the latest news is good. Of course, the primary cause of this defoliation was the huge population of spongy moth caterpillars in many areas of the county. Fortunately, most of the damage is over for this year. There are two reasons for this.
First, the caterpillars are now pupating, that is, they are no longer feeding but are transitioning to the adult moth stage. “How is that good news?” you ask. You have a point in that the female moths will be laying their sponge-like egg masses (hence the common name, spongy moth) later this summer on the bark of trees. These egg masses will be the source of next year’s caterpillars. The good news is there are fewer caterpillars that are pupating, and that gets to the second reason why the damage is ending and the future looks somewhat brighter.
Despite all efforts to try and control the ravenous caterpillars, it really had little effect in bringing down their population. Rather, it is Mother Nature who is more effective. I have already seen a significant number of the caterpillars showing signs of infection by either of two naturally occurring pathogens; one is a fungus and the other a virus. In the words of Tawny Simisky, UMass Extension entomologist: “Fungus-killed caterpillars will appear shriveled and dried, typically hanging vertically in a straight line on the trunks and branches of their hosts, or other surfaces nearby. Virus killed caterpillars tend to droop in an inverted-V shape and are often moist/juicy in appearance. The fungus and virus will hopefully help reduce the population of spongy moths in Berkshire County for next year.” (ag.umass.edu/landscape/landscape-message-june-24-2022).
On the bad news front, I saw the first Japanese beetle of the season 10 days ago on my raspberry plants and expect to see more as they steadily emerge from the soil through July and August. As with spongy moths, Japanese beetles feed on the leaves of many plants, both woody and herbaceous plants, including vegetable crops such as bush beans. The simplest strategy to manage this pest is to handpick the beetles or brush them from plants and into a container or soapy water. Do this daily, preferably early in the morning when the beetles are lethargic.
Staying with the bad news, jumping worms, also called crazy worms or snake worms, are now appearing. Currently the numbers are few but that is likely to change as the season progresses. Unfortunately, gardeners are very limited in what can be done to control this pest. There is much research currently being done to study the biology of these worms with the hope of finding some management tactics. For s review of current information about the worms, go to: ag.umass.edu/news-events/highlights/jumping-worms-conference
Back to good news, the weather has been quite favorable for plant growth and for gardening activities:
• Begin harvesting summer bearing varieties of red raspberries. A ripe berry is one that easily comes free when gently tugged. If the berry resists removal, though red in color, it is not fully ripe.
• Make your last planting of beans for the season. Also plant some leafy crops and cold crops i.e. fall cabbage, broccoli and cauliflower. Since these crops don’t like hot weather, water the plants well after they emerge and then mulch with straw or spoiled hay to keep the soil cool around the developing seedlings.
• Sidedress vegetables, especially long season crops such as tomatoes, eggplant, peppers, squash, and cucumbers, by applying a band of fertilizer around individual plants or by broadcasting between rows. Follow the product recommendations for dosage. Use a water-soluble fertilizer high in nitrogen on any plants showing significant yellowing of foliage (an indication of nitrogen deficiency.)
• Harvest broccoli when the heads are firm and tight, and before any flowering is evident. Leave the plant intact after harvesting the head and it will continue to yield much smaller but equally tasty side shoots for a few more weeks.
• Continue to prune off any side shoots from staked tomato plants. Staked plants should have only one or two stems. Also, prune off any leaves which appear on the lower foot of a stem.
• Trim and pinch back annual herbs such as basil and perennial herbs including oregano, marjoram, winter savory, lemon balm, sage and mints to keep them bushy and to prevent flowering.
• Revitalize petunias for another burst of bloom by cutting back the stems to just 4 inches above ground and fertilizing with a water soluble plant food. The plants will be in bloom again in about 2 weeks. Do the same for bachelor’s button.
• Give dahlias plenty of water throughout the summer since they don’t bloom well once exposed to drought. Pinch (ow!) and disbud plants to produce single stems and one flower per stem if you want large showy blossoms to impress friends. If you have no friends, leave the plants alone since they make better garden plants when allowed to develop multiple blossoms.