Perennial Hibiscus

[Sweetpea 0]

I have a tiny grey worm eating the leaves of my Hibiscus plants.  How can I get rid of these without using pesticides.  I know that I still will have flowers this fall, but in the meantime  the leaves look awful.

[Janet Macunovich 32]

There is a sawfly and also a moth caterpillar that might be the culprit. Both can be squashed, or knocked off with forceful water. (Insects are most often born on the plant they eat, they cannot find it from the ground, and there are also lots of predators on the ground looking for insects to eat.) Or soap can be an effective pesticide if they're young insects; the soap cracks ther skin, their skin is their skeleton, they die. If it's an oil based soap such as Murphy's oil soap then the oil also blocks the pores they breathe through and can smother them. Soaps and oils have no residual effect -- you have to aim them at the insects, so include the leaf undersides. Don't spray soap or oil on plants when it's very hot and dry or the plant tissue may be burned.

 

The one "nice" thing about insects is that although they may do ugly things they usually do it without killing the plant. There will be another year for the plant, one in which that particular insect may not be around in force, and there may even be recovery this same year after the insects have finished their life cycle.

 

Because it's good to know your enemy, here's more:

 

About the sawfly:

http://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/entomology/hibiscussawfly_rh_2014.pdf

images:

http://bugguide.net/node/view/4413/bgimage

 

Of interest: Read about the hibiscus you choose to buy, look for notes about inest resistance. At least one perennial grower/hybridizer we know has worked on breeding hibiscus that are resistant to this pest, and to Japanese beetle -- seems the key may be the fuzz on the leaf underside of some Hibiscus species, that some pests just can't eat through it:

http://www.ars.usda.gov/SP2UserFiles/Place/60620000/BoydPDF/jeh22(3)170-172.pdf

 

Anomis erosa is the abutilon moth or yellow scallop moth, a caterpillar that might be involved in hibiscus damage (the darned thing is not hardy to northern U.S. but can BLOW UP from Gulf states!)

It's green as a caterpillar, though...

Adult abutilon moths/yellow scallop moth: http://bugguide.net/node/view/170027/bgimage

 

The hibiscus moth caterpillar is another hibiscus pest; it doesn't fit you description for size and color but look for yourself:

http://bugguide.net/node/view/382796

[Michele A 2]

Do you know if any of these plants with resistance, especially to Japanese Beetle, will be available to buy?