Weather may leave us with a colorless autumn

Q. Why are the leaves so late in turning color? My understanding is that leaf color is due to the length of the days and the sugar/food in the tree for the leaves becoming depleted, not the temperature.

Is it the lack of rain? The overly warm fall? Will our leaves just dry up and fall off without much color change? A few of mine seem to be doing that -- and the fruit trees have really taken a hit.

Amy MacDonald, Batavia

A. Jack Frost seems to be sleeping on the job. Not only are the leaves late in turning color, but it seems as if they are indeed just drying up, turning brown and falling off.

No foliar fanfare, no breathtaking Kodak moments. It's as if the leaves are saying, "OK, we're done now. Start raking."

You're right on about the cues for the change in color. Day length is a primary trigger. Photosynthesis, or the production of plant sugars, also plays a role. And, yes, rainfall is involved in the mix.

For brilliant fall color, the best conditions are bright, sunny, cool days followed by cool nights and sufficient rain. We've been lacking on all counts. This fall we've had a combination of hot summer-like days, balmy warm nights and scant precipitation for six critical weeks.

So, we may have to take a pass on tree color this autumn and sigh, like the perennial Cubs fans, "Maybe next year."

Q. I am an amateur astronomer looking for a good site within the county for observing. Does the forest preserve have any locations that are well-suited for this activity? The sites need to be dark (limited or no street lights) and, of course, open at night. Any help would be appreciated.

Ed Bianchina

A. Astronomy is a great hobby to broaden your horizons. The quest for a dark night sky, however, is growing more difficult year by year.

Light pollution is an unfortunate by-product of "development," and there are few areas that are immune. The ubiquitous glow on the horizon -- north, east and south -- is now joined by light emanating from the west as more houses and shopping malls are built toward DeKalb County.

Please be aware that all forest preserves in Kane County close at sunset. We do, however, team up with the Kane County Astronomical Association to host after-hours astronomy programs and "star parties."

The locations are carefully chosen to take advantage of the few remaining areas with dark skies. In addition to Forest Preserve District/KCAA astronomy programs, the Fox Valley Astronomy Society also offers star parties at Peck Farm Park in Geneva.

For information about upcoming astronomy programs in Kane County forest preserves, call (847) 741-8350 ext. 10.

We can all help reduce light pollution. Check out the International Dark Sky Association for tips on improving the lighting around your home and minimizing the impact on the night sky. Visit www.darksky.org.

Q. I was wondering if you could help me figure out what is growing in our mulch. It grows quickly!

It begins looking like a wet, yellow mustard. Then it changes into an orange blob. If it's watered and allowed to grow more it explodes into powder all over.

I was wondering if you knew what it was and how to get rid of it.

Denise Janda, Batavia

A. Ah-ha! The infamous slime mold. The warm, moist weather that lingered until October brought a proliferation of this organism in gardens and lawns.

The yellow variety of slime mold that you describe is sometimes thought to be -- no kidding here -- dog vomit. I've even heard of people taking their dog to the vet thinking that the dog is getting ill at night when, in fact, the blob on the mulch is not Rover's doing at all.

Slime molds are unique organisms that are neither animal nor plant. They are somewhat akin to fungi, as they do not possess chlorophyll and cannot make their own food.

They feed on bacteria, fungi and dead animals and plants -- hence, they are happy in your mulch. They are motile -- in other words, they can actually move on their own.

Weirder still is the fact that the big yellow blob on your wood chips is one large, single cell with myriad nuclei. This type of one-celled blob has been clocked at a whopping speed of 1 millimeter per hour. The explosion you describe is made of the spores, by which the slime mold reproduces and makes more dog vomit.

The slime mold may not be attractive, but it's not harmful, so you may opt to do nothing but ignore it. If you do want to get rid of it, sometimes raking the mulch helps by drying it out. Or you might try blasting the colony with the garden hose. But, as with the Blob of sci-fi fame, you'll never know if it's really gone.

Q. Is our lawn the only one that has been full of holes dug by big wasps? In August these insects began buzzing us and digging deep holes 6 to 8 inches across. We actually saw them flying with cicadas in tow. Since the cicadas' bodies were larger than those of the wasp, the flight was a struggle. They did succeed in getting several cicadas in the holes.

John D. McDonald

A. The large wasps that excavated your lawn are Cicada Killers. Cicada Killer wasps are not uncommon, and they are most visible when cicadas are out and about.

You undoubtedly had an abundance of cicadas this summer and, judging from the predation activity you describe, you will have an abundance of Cicada Killers next summer.

The female wasps in your yard were paralyzing cicadas, dragging their big, immobile prey underground and laying eggs in the cicadas' bodies. As the larvae matured, they ate the cicadas from the inside out.

Now that the leaves are falling, the Cicada Killers' tunnels will soon be lost and the larvae will be safely ensconced in cocoons underground.

To add to the "Wild Kingdom" flavor of the story, the Cicada Killer wasp itself may be parasitized by another type of wasp known as a Velvet Ant. This wasp lays its eggs inside the pupal stage of the Cicada Killer, and the developing Velvet Ant larva devours the Cicada Killer pupa.

It truly is a dog-eat-dog world out there.

• E-mail your nature questions to Valerie Blaine at blainevalerie@kaneforest.com. Or send mollusk mail to Valerie at Tekakwitha Woods, 35W076 Villa Marie Road, St. Charles, IL 61074-6692.