This is an annual problem usually starting in May in Maryland but in dry, hot years the damage seems worse.
The curled and twisted tip growth is caused by a pest called potato leafhopper.
 Generally, the potato leafhopper (Empoasca fabae) cannot overwinter in the North because of sensitivity of the eggs to the cold though on occasion, the leafhopper has been found overwintering in the southern area of the Eastern Shore of Maryland. The potato leafhopper is found year-round in the Gulf of Mexico. In May and June the prevailing northern winds carry the leafhoppers into the jet stream and drop them out in states such as Maryland.

Potato leafhopper nymphs and adults have piercing-sucking mouthparts and feed in the vascular tissue- as the stylet probes the plant tissue, internal cells are lacerated and salivary toxins injected into tissues cause the cells to collapse. When vascular tissue is damaged in shoots, the tip growth tissue becomes distorted. This feeding by the leafhopper causes tip growth on the maples to curl over and harden. This damage is typically referred to as ‘hopperburn’.
We suggest you do nothing other than try to keep your trees as stress-free as possible. Last year many parts of Maryland had prolonged, serious drought conditions, and many trees, including mature ones, suffered. As it gets hot and dry now, those trees will show more stress.
If you can offer supplemental water when we don't get at least an inch or two of rain a week, do so.
We can't tell from your photos if there may be other issues or site problems, but if the trees are important to you, you could consider having an ISA- certified arborist come and take a look and advise. Most larger tree companies have them on staff or you can search for one at the credentialing agency here: 
http://www.treesaregood.org


Christine

Thank you so much for the quick response.  Would I see evidence of this pest?  I have not been able to see anything on the trees?

Hello Doug,

Leafhopper nymphs (juveniles) and adults can be fairly small, but are readily visible if leaves are inspected (if they insects are present at the time). They tend to remain on the leaf underside.

Another possible diagnosis, especially if the entire canopy is affected (and is that bad on multiple trees), is herbicide damage, which is a type of phytotoxicity. Since they suggested the same, we agree with the tree company's opinion in this case. Is that a agricultural/farm field behind the tree in the photo? If so, that strongly supports the theory that herbicide drift (airborne chemical from an application) wafted over the maples and impacted their growth. Some tree species are more sensitive to certain chemicals than others, and drift won't always land on every nearby plant in equal dosage. If airborne, drift might carry for some distance, so woodland trees could also be vulnerable depending on the chemical applied and its dosage, the weather conditions during and after application, and how stressed by other factors the trees might have been at the time.

Sometimes herbicide exposure is only cosmetic and plants eventually recover with normal-looking replacement growth, but sometimes either their sensitivity is too high or the exposure was too great, and recovery is not possible. There is no way to counteract an exposure after the fact, except perhaps leaching something out of the soil if a chemical moved off-site in irrigation or rain runoff. (Airborne exposure is more common and more likely, especially in this situation, so that would not apply here.)

Drought stress can compound symptoms of many ailments, so keeping them well-watered will certainly help boost their chances at recovery, if recovery is possible. (Time may tell if it is.) Maples tend to appreciate soils that don't get too dry, though Red Maple (the species 'October Glory' is a variety of) can handle it wetter than most, and is probably among the first of our local maple species to get stressed by prolonged dry weather.

Fosphite appears to be a fungicide, labeled for use in the suppression of various root-rotting pathogens. While such treatments sometimes succeed in suppressing those organisms, they are not long-term solutions. (Whatever conditions predispose a tree to its infection, like poor drainage, needs to be addressed.) They also cannot cure existing infection or directly reverse the root loss it causes.

These microbes are very common in most soils, and are only a problem if the host plant is first stressed by low soil oxygen levels in the root zone (usually from heavy soil compaction or sogginess) or some other environmental condition. Unless the arborist has demonstrated that some of the trees were succumbing to root rot in particular, we don't see a reason to use that fungicide. This is especially the case since Red Maples tend to fare well in fairly damp soils, and these don't appear to be showing signs of chlorosis, a nutrient deficiency that indicates soil acidity (pH) incompatibility, which can be another root stressor causing acid-loving plants to be vulnerable to those kinds of root infections.

If this is herbicide injury, the trees will just need to grow out of it on their own, if they are capable of doing so, and hopefully a repeat exposure doesn't happen next year if a nearby farm is routinely using herbicide on weeds or a cover crop. If this is "hopper burn," then similarly nothing needs to be done, and regrowth will appear in its own time, since leaf damage cannot heal. Insect populations can rise and fall from one year to the next, so an outbreak won't necessarily repeat itself the following year.

Miri

Thank you for the quick response.

You're welcome.
It sounds like herbicide drift is the most likely scenario, then. Hopefully it wasn't too heavy an exposure this year, and the farm doesn't repeat the situation next spring.

Miri