Because squash bugs feed by sucking juice from the plant, only insecticides that directly contact the insect will work. General use insecticides such as permethrin (Bug-B-Gon Multi-Purpose Garden Dust; Green Thumb Multipurpose Garden and Pet Dust; Bug-No-More Yard and Garden Insect Spray; Eight Vegetable, Fruit and Flower Concentrate; Garden and Farm Insect Control; Lawn & Garden Insect Killer), malathion, and methoxychlor provide control if a direct application is made to young, soft-bodied squash bugs. This means that you MUST spray or dust the underside of the leaves because this is where the insects live. (Ward Upham)
Squash bugs are the grey, shield-shaped bugs that feed on squash and pumpkin plants. If you have had problems with these insects in the past, you know that they are almost impossible to control when mature. This is because the squash bugs have a hard body that an insecticide has difficulty penetrating. Thus, spraying when the insects are small is important. Look on the underside of the leaves for cluster of brick-red eggs and small green insects with black legs. These nymphs will eventually become adults, which will lay eggs that will become the second generation. The second generation is often huge and devastating. Therefore, it is important to control as many squash bugs of the first generation as possible.
Because squash bugs feed by sucking juice from the plant, only insecticides that directly contact the insect will work. General use insecticides such as permethrin (Bug-B-Gon Multi-Purpose Garden Dust; Green Thumb Multipurpose Garden and Pet Dust; Bug-No-More Yard and Garden Insect Spray; Eight Vegetable, Fruit and Flower Concentrate; Garden and Farm Insect Control; Lawn & Garden Insect Killer), malathion, and methoxychlor provide control if a direct application is made to young, soft-bodied squash bugs. This means that you MUST spray or dust the underside of the leaves because this is where the insects live. (Ward Upham)
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Yellow nutsedge is a relatively common problem in lawns, especially in wet years or in lawns with irrigation. Although sedges look much like a grass, they are different.
Unlike grasses, sedges have triangular stems, and the leaves are three-ranked instead of two-ranked, which means the leaves come off the stems in three different directions. Yellow nutsedge is pale green to yellow and grows rapidly in the spring and early summer. Because of this rapid shoot growth, it sticks up above the rest of the lawn only a few days after mowing. This weed is a good indicator of poor drainage, but it can be introduced into well-drained sites through contaminated topsoil or nursery stock. As with many weeds, nutsedge is less competitive in a dense, healthy lawn than in an open, poor lawn. Nutsedge is difficult to control culturally because it produces numerous tubers that give rise to new plants. Pulling nutsedge will increase the number of plants because dormant tubers are activated. However, it is possible to control nutsedge by pulling, but you must be persistent. If you are, eventually the nutsedge will die out though this will likely take more than one season. If you were going to treat with an herbicide, it would be better to leave the nutsedge plants undisturbed so the herbicide can be maximally translocated to the roots, rhizomes, and tubers. Several herbicides are available for nutsedge control. SedgeHammer and Hi-Yield Nutsedge & Horsetail Control contain halosulfuron and are effective and safe products. The SedgeHammer label says to apply after the nutsedge has reached the three- to eight-leaf stage. Waiting until this growth stage apparently results in improved translocation of the active ingredient to the underground tubers and rhizomes. Products with sulfentrazone such as Bonide Sedge Ender, Ortho Nutsedge Killer and Spectracide Weed Stop for Lawns Plus Crabgrass Killer are also effective. Research has shown that the first application should go down by June 21. If the initial spray is after June 21, mature daughter tubers may be stimulated to grow. (Ward Upham) If you plan on using a grub preventative on your lawn, the first half of July is a good target date for most products. Preventatives are normally used on areas that have had a history of grub problems. Traditional grub insecticides such as Dylox or carbaryl (Sevin) are normally applied in late July after grubs are present or as a rescue treatment once damage is seen. Products that contain Merit (imidacloprid) are considered grub preventers. Actually, these products do not prevent grubs, but rather kill grubs when they are quite small, and long before they cause damage. Merit is safer to use around pets and humans than traditional grub killers. Merit can be found in BioAdvanced Season-Long Grub Control, Bonide Grub Beater, Gordon’s Grub No-More and Hi-Yield Grub Free Zone II and III. Another grub preventer with the trade name GrubEx contains chlorantraniliprole. Though this product is very effective, it is less water soluble than imidacloprid. It should be applied earlier, preferably April or May, but applications through June should still be effective. Remember, all grub products should be watered in soon after application. (Ward Upham) Stress is cumulative. In other words, trees and shrubs can be affected by stresses that happened up to several years in the past. Recent stresses in Kansas include sharp drops in temperature in the fall before some trees had hardened off. This occurred in both 2019 and 2020. This was followed by last fall and winter’s extremely dry weather which often resulted in damaged root systems. This damaged root system may have been further weakened due to too much rain in some part of the state this spring. The excess water harmed root systems due to saturated soils driving out oxygen. Roots need oxygen as much as they need water. Though the roots were able to keep up with moisture demands during the cooler spring weather, they may not be able to keep up when the weather turns hot and dry. Such trees and shrubs may suddenly collapse and die or slough off branches they can no longer support. This does not mean that all of our plants are doomed. Some plants are just better adapted to our tough Kansas conditions and have suffered little to no harm. However, it is a good idea to check the overall health of your trees. So how do you tell? One of the most important clues in determining the health of your trees is the amount of new growth that tree has produced. A healthy tree should have a minimum of 4 to 6 inches of new growth each year and usually much more. Check branches with the tips in the open and not shaded by the tree itself. Anything less than 4 inches on the majority of branches suggests the tree is under a great deal of stress. We had an article in this newsletter last week that showed what to look for. The only thing poor growth tells you is whether a tree is under stress or not. It does not tell you what is causing or has caused poor growth. This year, the most common cause by far is environmental stress caused by the dry fall and winter followed by excessive rain this spring. So, what do we do for trees under stress? The most important practice is to water as needed. See last week’s newsletter for information on proper watering practices. (Ward Upham) Many gardeners look forward to harvesting new potatoes at this time of year. New potatoes are immature and should be about the size of walnuts. Pull soil away from the base of the plants to see if the tubers are the desired size. If they are, dig entire plants and allow the skins of the exposed tubers to dry for several hours before gathering. These young potatoes are very tender and prone to the skin “slipping” unless they are given a few hours to dry. Even then these immature potatoes will not store well. Red-skinned varieties are often preferred as they are the earliest to produce. (Ward Upham) Though tomatoes need to be fertilized to yield well, too much nitrogen can result in large plants with little to no fruit. Tomatoes should be fertilized before planting and sidedressed with a nitrogen fertilizer three times during the season. The first sidedressing should go down one to two weeks before the first tomato ripens. The second should be applied two weeks after the first tomato ripens and the third one month after the second. Common sources of nitrogen-only fertilizers include nitrate of soda, urea, and ammonium sulfate. Blood meal is an organic fertilizer that contains primarily, but not exclusively, nitrogen. Use only one of the listed fertilizers and apply at the rate given below. Nitrate of soda (16-0-0): Apply 2/3 pound (1.5 cups) fertilizer per 30 feet of row. Blood Meal (12-1.5-.6): Apply 14 ounces (1.75 cups) fertilizer per 30 feet of row. Urea (46-0-0): Apply 4 ounces (½ cup) fertilizer per 30 feet of row. Ammonium Sulfate (21-0-0): Apply 0.5 pounds (1 cup) fertilizer per 30 feet of row. If you cannot find the above materials, you can use a lawn fertilizer that is about 30 percent nitrogen (nitrogen is the first number in the set of three) and apply it at the rate of 1/3 pound (3/4 cup) per 30 feet of row. Do not use a fertilizer that contains a weed killer or weed preventer. (Ward Upham) Fruit gardens have certain chores that need to be done through the growing season such as the following. * Remove some fruit from heavily loaded apples and peaches (if the flower buds weren’t killed by frost) to improve fruit size and prevent limbs from breaking. Apples and peaches should be spaced about every 6 to 8 inches. Note that is an average spacing. Two fruit can be closer together if the average is correct. * Remove sucker growth from the base of fruit trees and grape vines. * Remove water sprout growth from fruit trees. Water sprouts grow straight up from existing branches. * Water as needed. About 1 inch of water per week is about right though more may be needed during hot spells. * "Comb" new growth on grape vines so these new shoots hang down for greater exposure to sunlight. * Continue disease and insect control to prevent fruit damage. For more detail on fruit sprays, see “Spray Schedules” on our publication page. (Ward Upham) One of the most important clues in determining the health of your trees is the amount of new growth that tree produces. A healthy tree should have a minimum of 4 to 6 inches of new growth each year. Check branches with the tips in the open and not shaded by the tree itself. Anything less than 4 inches on the majority of branches suggests the tree is under a great deal of stress.
So how do you tell where the new growth stops? Look for a color change in the stem. New growth is often greener than that from the previous year. There is also often an area of what looks like compressed growth where growth transitions from one year to the next. Lastly, look at leaf attachment. Leaves are only produced on current season’s growth. Therefore, new growth stops where leaves are no longer attached directly to the twig but to side branches. However, pay attention as leaves may be appear to be attached directly to last year’s growth but are actually borne on short spurs. If you look closely, you can tell the difference. All this clue tells you is whether a tree is under stress or not. It does not tell you what is causing poor growth. Stress is cumulative. In other words, trees may not have completely recovered from stressful conditions (such as drought) that occurred within the last several years. The accumulating stress may have damaged root systems with further damage occurring due to the dry soils last fall and winter. These trees may struggle as we enter summer. Though the roots were able to keep up with moisture demands during the cooler spring weather, they may not be able to as temperatures rise. Such trees may suddenly collapse and die or slough off branches they can no longer support. If possible, water to a depth of 12 inches every couple of weeks we do not receive rain in order to avoid further stress. (Ward Upham) Most calls on how to control bagworms come in during late-July to early-August when damage appears. Bagworms are difficult to control when they are that large. They are much easier to kill while small. Bagworms overwinter as eggs inside the dead female’s bag. Young larvae normally hatch and emerge during mid- to late-May in Kansas. Now would be a good time to scout for bagworms. Wait to use control measures until mid-June as earlier sprays may miss those who emerge from the bag later than normal. However, make sure the bagworms are present by looking for a miniature version of the mature bagworm. Also, check to be sure the bagworms are alive before spraying. Predators and parasites can sometimes naturally control this pest. Insecticides commonly used for controlling bagworms include: acephate (Orthene) permethrin (38 Plus Turf, Termite & Ornamental Insect Spray; Eight Vegetable, Fruit & Flower Concentrate; Garden and Farm Insect Control ) bifenthrin (Bug Blaster II, Bug-B-Gon Max Lawn and Garden Insect Killer) lambda-cyhalothrin (Spectracide Triazicide, Bonide Caterpillar Killer) spinosad (Conserve; Natural Guard Spinosad; and Captain Jack's Dead Bug Brew). Spinosad is an organic control that is very effective on this pest. Thorough spray coverage of foliage is essential for good control with any of these products. (Ward Upham) |
AuthorsCynthia Domenghini runs the Horticulture Response Center in the Department of Horticulture and Natural Resources at Kansas State University. Other contributors include K-State Extension Specialists. Archives
March 2024
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