No. 9/June 20, 2016
Boxwood Blight Special Screening Service
Boxwood Blight is an exotic fungal disease which can infect members of the Buxaceae family. It has been confirmed on boxwood, pachysandra, and sarcococca. It was first described in the United Kingdom in the mid-1990s. Since then, it has been found throughout Europe and in New Zealand. The pathogen was identified for the first time in the United States in 2011. To date, this disease has not been found in Illinois.
Austrian pines are showing symptoms of Diplopia (Sphaeropsis) tip bight. This disease is prevalent in Illinois, especially in years when we have lengthy, cool, and wet spring weather. Diplodia is a fungal disease that mainly affects two- or three-needled pine species. White pine, Spruce, fir, Douglas fir, and other evergreen species are also potential hosts, but are less affected by the disease.
Few people like 90+ degree temperatures. Plants aren’t far behind. On hot days, plants can lose water faster than roots absorb it, even if sufficient soil moisture is available. In these conditions, you can watch the plants wilt, leaves droop, and stems seem to flop. If the soil is moist, the plants start to recover as the sun sets. By morning, they look turgid, only to begin the cycle again when the sun shines hard. This is what we are currently seeing in Illinois.
Strawberry Root Weevil
Strawberry root weevils are smaller relatives of black vine weevil, causing similar damage to a wider array of plant species. The adults are hard-shelled, blunt-snouted weevils about one-quarter inch long. Those that have newly emerged from pupae are brown and slowly turn black. They have no spots or other distinguishing markings. Like black vine weevils, they emerge at this time of year and are long-lived, with some entering houses and surviving through the winter.
Horsehair worms are being found in mud puddles and road ruts after rains. They are very slender, whitish to dark brown, nematode-like worms usually four to seven inches long. These are adult worms that have emerged from their insect hosts to reproduce. Male and female worms shed their gametes (sperm and eggs) into the water where fertilization takes place.
The weather is finally warm (almost hot) and the planters are rolling full speed across central Illinois. Gardens are being planted as well. Planting preparation in farm fields often includes the use of herbicides to kill off any unwanted weeds that have set up residence this spring. Invasive species and other miscellaneous weeds in non-crop areas are being sprayed as well. 'Tis the season for much growth, and much death of plants. We humans are kind of funny like that.
Modified Growing Degree Days (Base 50°F, March 1 through June 16)
Insect development is temperature dependent. We can use degree days to help predict insect emergence and activity. Home, Yard, and Garden readers can use the links below with the degree day accumulations above to determine what insect pests could be active in their area.