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The spotted lanternfly population has grown considerably after last winter’s mild weather.

As the result of a mild winter, the spotted lanternfly population has become enormous this year. In many of the affected areas in early August, trees were completely covered with feeding nymphs.

Unsurprisingly, reports of spotted lanternfly from locations previously considered uninfested are significantly on the rise in southeastern Pennsylvania.

There is limited information on pesticide options for control of spotted lanternfly because is it a new pest in this country.

This year, Penn State Extension is conducting efficacy trials on products that are available to the homeowner for control on private property.

Last month, Extension began testing contact insecticides including horticultural oil, neem oil, insecticidal soap, and products that contained spinosad, carbaryl, bifenthrin or pyrethrin as the active ingredient.

Two systemic insecticides — both applied as soil drenches and one as a bark spray — were included in the preliminary trials.

Initial observations suggest that some active ingredients produce better control than others. Products with active ingredients of bifenthrin, pyrethrin and carbaryl appeared to have an immediate effect on caged lanternflies.

There was some effect from neem oil and insecticidal soap, but results were variable. Also, the insects were not killed immediately with these products. It took several days to see the full effect.

For the systemic products, the bark spray with dinotefuran as the active ingredient appeared to outperform the dinotefuran and imidacloprid drenches.

The researchers speculate that the drenches may do better if applied to the soil earlier in the season and are considering changing their study design for next year.

The 2017 study is a preliminary effort and researchers have not completed collecting the data for the season.

Adult spotted lanternflies started emerging in early August. The females are not reproductively mature at emergence.

There are indications that the females must feed on the tree-of-heaven trees — Ailanthus altissima — at some point in order to complete the life cycle.

However, the number of hosts on which the insect can complete its life cycle is not known at this time. Other researchers are trying to identify primary and secondary host plants distinct from plants the lanternfly targets for opportunistic or accidental feeding.

Penn State Extension is also monitoring the population for general reproductive status to adjust control tactics to target pesticide applications prior to the onset of oviposition to reduce the population of the following year.

For information on the Pennsylvania Department of Agriculture’s Spotted Lanternfly Program, visit http://bit.ly/2k8WPps,

Source: Amy Korman and Emelie Swackhamer, Penn State Extension.

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