Grasshopper populations were very high last year in many areas of northern Utah, and are predicted to be high again. In some areas of Tooele County, over 100 nymphs/square yard have been reported this spring. Grasshoppers are easiest to control in the nymphal stage.
Now is the time for communities or neighborhoods to work together to suppress populations. Treating as wide an area as possible is the key to success. As adults, grasshoppers can travel great distances and may not remain in one area long enough for an insecticide to be effective.
Grasshopper feeding injury on vegetable plants results in random, ragged holes in leaves. This type of feeding will not cause a reduction in yield, but grasshoppers have been known to cause severe damage in high numbers They are most common where vegetable fields border rangeland, pasture, roadsides, fence rows, etc.
Grasshoppers overwinter as eggs and hatch in mid to late spring. They thrive in hot, dry seasons. Population sizes vary from year to year depending on a variety of factors (weather, diseases, vegetation, etc.) so keep in mind that eventually the populations will decline.
Treatment: carbaryl+bait (Corry’s Bug BaitH, Eco Bran, Lilly Miller Grasshopper Bait, Sevin 5 Bait), carbaryl (SevinH, many others), permethrin (Basic Solutions, Bonide EightH, GordonsH, SpectracideH, etc.), bifenthrin (Tundra, Allectus, Brigade, Sniper, Talstar), acephate (OrtheneH), malathionH
Flea beetles have been active on a variety of cole crops in Cache County. Warm spring weather speeds their activity. Cole crops are the primary host, while other vegetables (sweet corn, tomatoes) are secondary. Some crops can be more severely impacted than others, such as arugula and mustard greens.
Flea beetles are tiny black beetles that jump when disturbed. They overwinter as adults and begin feeding in spring. They feed on the undersides of leaves causing small holes or sunken pits. Although they are present throughout the season, they are mostly a problem on new seedlings, and if left unchecked, can cause significant damage. Older plants can usually withstand feeding, although the lower leaves may be affected.
Monitor young seedlings carefully until they have mature leaves. The best time is mid-day when they are most active. Note that older plants can tolerate 20-30% damage on leaves before a reduction in yield.
Treatment: spinosad (Entrust, Success, MontereyH, Ferti-LomeH, etc.) insecticidal soapH, diatomaceous earth, neem oilH, carbaryl (SevinH), permethrin (Ambush, Pounce)
Powdery Mildew of Cucurbits
Powdery mildew infections will soon start showing up on melons, pumpkins, and other cucurbits. Mild infections will not harm the plant or the crop, but a severe infection can kill the plant.
The key to managing powdery mildew is good monitoring, and prevention early in the season. Examine all plants in the small garden, or walk through fields once, and examine the upper and lower surfaces of five older leaves of each plant (or of 10 random plants). Once symptoms are found on 10% of the plants, plan to treat.
Treatment: sulfurH, mineral oilH, and chlorothalonil are very effective; other options are: neem oil (Bonide Bio-NeemH, Concern FTE, Garden SafeH), surround (Kaolin Clay), potassium salts of phosphorus acid (Fosphite, Fungi-Phite), copper (Kocide)
Halso for homeowner use
The currant aphid has been feeding on red and white currants and gooseberries this spring. As it feeds, it causes cupping and leaf deformation. Leaves turn red to yellow at feeding sites. Honeydew drips on leaves and developing fruits.
This aphid overwinters as shiny black eggs on currants, and then a small population moves to an alternate herbaceous host for the summer. Usually damage is not serious enough to warrant treatment.
Treatment: oil during dormant season; strong wash of water; neem oilH, rotenone, insecticidal soap.H
Halso for homeowner use