October 13, 1995
Yellowjacket wasps are common insects in Iowa that build annual colonies in the ground, or in holes in building walls and foundations. These inner-wall nests are often the source of wasps that will invade the living space within the house, especially in the fall and early winter.
Sooty blotch and flyspeck are caused by two different fungi that usually occur together on the same fruit. Sooty blotch appears as superficial, dull black spots or blotches that may merge to cover most of an apple. Flyspeck appears as clusters of 6 to 50 or more slightly raised, black shiny round dots that resemble fly excreta.
Because the fungi that cause sooty blotch and flyspeck grow superficially on the surface of the fruit, losses are primarily through lowered quality. (The black discoloration can be removed by vigorous rubbing.)
Unlike the drought years of the late 1980's, this will probably be another year when boxelder bugs are a limited problem. There will, however, be enough boxelder bugs to cause major annoyance for some people. Therefore, now is the time to brush up on boxelder bug life cycle and controls.
Conifers (evergreens) Showing Fall Color I have had many calls in the last few weeks concerning the abrupt discoloration of the interior needles in many different types of conifers. The good news in most cases, is that this is a normal characteristic of many different conifers in the fall, and not some fatal disease.
Judging by the number of calls coming into Hortline this year, Iowans must have grown a record number of gourds. That shouldn't be surprising since gourds are among our oldest and most useful domesticated plants. They vary from the luffa sponge used for bathing and cleaning to the long handled dipper gourds. They are used for everything from bottles to fishing floats, from seed containers to musical instruments.
This is the time of year evergreens arrive in the Plant Disease Clinic showing symptoms of seasonal needle loss. People often mistake this normal discoloration and loss of needles for an infectious disease problem.
Evergreens do not keep their needles indefinitely. Older, inner needles senesce, turn yellow or brown, and drop from the tree after one to several years depending on the tree species.