After a long, snowy and brutally cold end to the winter in many parts of the country, spring is finally here. But conditions are still a little behind normal, about two weeks in the Eastern half of the U.S., and even further behind in New England, says Jill Calabro, Nufarm plant pathologist.
Out West, however, conditions have been warmer and drier. “So when conditions are dry, generally the pest pressure is a little bit lower in most cases, but everything is warmer so things are sped up a little bit, especially in the Pacific Northwest and California,” Calabro says.
Northern pests
Annual bluegrass weevil. Applications should start in April as these start to lay eggs, says Jeff Marvin, manager of field research for PBI/ Gordon. You can also apply in May to target the pupa of new annual bluegrass weevils. To spot them, look for yellowing patches in bluegrass turf.
Grubs and billbugs. While pressure isn’t too bad early in the season, Calabro says, there could be some springtime damage from grubs that were not properly controlled last season. “The recent cold and wet weather has made it hard to get preventative treatments out on time,” she adds.
Grubs are easiest to control with preventative applications in the spring. Curative treatments can be done in the summer, but control is much more difficult, Marvin says.
According to Dean Mosdell, Syngenta technical manager for the Western U.S., grubs of several beetle species in the area can cause significant turf damage in late summer as they feed on roots. Look for dry, brown patches in the lawn and check the soil moisture. If the soil isn’t dry, give the lawn a good pull. If it comes up easily, grubs or billbugs are most likely eating away at the root system.
Billbugs are a persistent problem and feed on turf in the early summer, especially on Kentucky bluegrass lawns, Mosdell says.
A good imidacloprid product should solve the problem with an application and a follow-up two weeks later. The lawn will require extra watering after grub damage in order to establish new roots.
Southern pests
Chinch bugs. These pests could be a problem on St. Augustine grass, Mosdell says. While their damage looks like drought or root rot, the bugs can be identified on closer inspection. Simply cut the end off a coffee can and insert it in the ground. Pour water into it for about five minutes and see if the bugs float to the top. Chinch bugs love nitrogen, so be wary of over fertilizing, as it can actually help the bugs mature faster and lay more eggs.
Fall armyworm. This is a problematic pest in the South, and is most severe in late spring through summer, depending on the region, Marvin says. Affected areas will yellow and the turf will thin, and most infestations start near a wood line or tree. You can spot the ½ to 1-inch caterpillars on visual inspection. Technicians servicing Bermudagrass should especially be on the lookout Mosdell says.
Fire ants. According to the Bayer Green Solutions Team, fire ants will be active once the weather warms up, so now is a good time to treat for them. “Fire ants are like people. If the weather is mild, warm, but not too hot, they become very active. If it gets too hot, they’re not nearly as active.”
Ornamental pests
Mites. “Mites are typically active during periods of drought or stress to plants,” PBI/Gordon’s Marvin says. Depending on the weather, that can range from spring to fall. You can spot the pests’ damage by looking for bronzed or chlorotic leaves.
Thrips. Thrip damage looks like a small silver line or vein on a leaf. “Thrip damage may also result in stunted plant growth and leaves that appear distorted,” Marvin says. Be sure to look at the undersides of leaves as that’s where most of the damage occurs. Silken webs may also be present around the infested plant parts, he says.
Invasive species
Emerald ash borer. Emerald ash borer has spread into Colorado, southern Arkansas along the Louisiana border and even into Georgia, Calabro says. “It is continuing to spread so we’ll probably start seeing more positive identifications in areas that previously had not seen emerald ash borer, but the signs of that pest, you wouldn’t even notice early in the spring.”
The bug has been in the news recently as it is now infesting white fringtree. Wright State University professor Don Cipollini found evidence of EAB attacks on specimens in Ohio during the summer and fall of 2014.
Signs of infestation include canopy dieback, shoots growing from the trunk or root zone, bark splitting at the beetle’s entry point and callus tissue formation around the bore hole as well as epicormic shoots, which can be seen as larger than normal leaves.
Bore holes are D-shaped and tunneling or galleries may be visible if the bark is peeled away, Marvin says. Increased woodpecker activity can also be a sign of an infestation.
If you are servicing areas where EAB has been spotted, be sure to treat in the spring. The optimal time to make applications is before adults emerge early to mid-April. However, there are treatments available for summer months such as dinotefuran, which can be applied via a basal trunk spray or a soil treatment.
Pine mountain beetle. Pine mountain beetle is another one to look out for, especially in western states, according to Calabro. Adults range in size from ?-inch to 1¼-inches.
“Needles that turn a reddish brown color are characteristic of pine bark beetle damage and needle cast during severe cases,” Marvin says. “Trees under stress are typically infected first. Reddish boring dust is visible at that time.”
To control the bug, infested trees should be removed and burned or chipped as most trees that have been infested will eventually die.
“Treatment must be applied to target the adults when they land on the trees,” Marvin says, but he cautions that applications could also target beneficial insects.
Japanese beetles. Adult Japanese beetles typically become active down south around late May, and in northern regions in late June to July, Marvin says. Look out for trees or shrubs losing leaves, which can happen within a few days. And be on the watch for the beetles, which are large enough to see with the naked eye, he says.
Be ready for action.
Technicians should be on the lookout for signs of injury from insects, which generally look like thinning turf, off-color or browning foliage, Mosdell says. While turf may look like it’s suffering from drought, it’s important to dig down into the thatch or soil to find the cause of problems.
To deal with early season pests, Calabro recommends keeping a good broad spectrum product on hand so that technicians can put down treatments right away.
“LCOs should be able to identify the ornamental plants and assess the overall health of the shrub and tree,” he says. “Sometimes nutrition may be the key factor but examination of the tree or shrub may reveal other issues. Many times pests are host-specific so identification of the plant is important.”
Marvin says it’s best to target problems with preventative applications. He also says it’s important to actively monitor and scout properties to ensure that applications are made right when they’re needed.
