getting rid of Japanese beetles
Their populations should begin to decrease dramatically within the next one to two weeks without any application of pesticides. Their populations are naturally on the decline around mid-August.
Applications of Sevin or any of the pyrethroids (active ingredient ends in "-thrin") will provide about 7 - 10 days control. Neem oil is another product that can be used but may more frequent applications and this is also influenced by the weather (especially rain).
Hand-picking and placing in soapy water is the best non-chemical option; however, it needs to be done frequently. Usually once in the morning and once in the evening is the minimum needed to have any efficacy. This can be a time consuming activity depending on the number of plants you have and are trying to protect.
Thanks, Brian. Are both Pyrethroids and Neem oil safe for the pollinator insects ? Karen
Pyrethroids are products found in the wasp killing aerosol cans; thus they are not very 'safe'. They are what is referred to as broad-spectrum products--meaning they will kill a variety of insects. Neem oil is probably safer than pyrethroids; however, I'd read to label to make sure if there is any warning language in reference to pollinators. Most insecticides on the market have adverse effects on bees. Applications should be made when pollinators are not present and by following the label included with the product.