You might find lions and tigers and bears frightening, but farmers and gardeners might disagree.

Groundhogs and rabbits and deer can be more destructive.

And then there are the fungi. Early blight, late blight and anthracnose. Black spot and mildew and scab. Rusts and rots and wilts. It’s a jungle out there!

Fungi are certainly the most common organisms associated with plant disease; “associated” because the pathogen, by itself, does not equal disease. A susceptible host plant and the proper environment are also necessary.

Here’s an example. Tomato growers might be noticing brown spots and perhaps yellowing of the lower leaves. On closer inspection, you may see that the “spot” is actually a lesion that has concentric rings of dead tissue. There may be tiny black dots in the dead tissue.

As the season progresses, more and more foliage is killed. Fruit infections cause soft spots and rots.

All of these symptoms describe the common tomato disease called early blight. The disease also affects potato and eggplant. You may be happy to learn that the weeds horse nettle and black nightshade are vulnerable, too.

Since all these plants are related, it is not surprising that they are susceptible hosts for the same pathogen. Note that the early blight pathogen has no effect on asparagus, beans or cucumbers.

When there is a susceptible plant and a pathogen, the final ingredient needed for disease is the proper environment. The pathogen thrives and reproduces well under warm, moist conditions.

Tomatoes are especially vulnerable that are left to sprawl on the ground rather than trained to a support system which favors air movement and leaf drying.

You can manage this disease by thinking about three key disease ingredients: pathogen, host and environment.

Sometimes it is possible and effective to eliminate the pathogen. But it can be equally effective to grow non-susceptible host plants or modify the environment.

Disease resistant varieties have been developed for many of our favorite plants. Look for them when buying seed.

Learn about the conditions that favor disease. Do what you can to change it. For most fungal diseases, that means increasing air movement and reducing leaf wetness.

Following are some other things that you should be doing now:

Monitor tomato plants for tomato hornworm and remove them by hand.

Deadhead flowering annuals to promote continuous bloom. If you want them to reseed in September, allow “spent” flowers to remain on the plant to produce seed.

Plant seeds of squash, cucumbers, beans, and other heat-tolerant vegetables. There are at least three months of growing time left.

Prepare some garden space for fall crops of lettuce, green beans, carrots, beets and spinach.

Leave room to plant garlic in October.

Give the lawn a break from weed control and fertilizer products until September. Continue to mow at least 2-1/2 inches high and let nitrogen-containing grass clippings stay on the lawn.

Harvest garlic in mid-July when about half of the lower leaves are brown.

Divide iris in late July and divide peonies and daylilies in August. The iris leaves can be cut back to eight inches.

Master Gardeners: The Blueberry Festival is July 13 and 14, Burnside Plantation, 1461 Schoenersville Road, Bethlehem. Lehigh and Northampton County Master Gardeners will be there to answer your gardening questions.

“Growing Green” is contributed by Diane Dorn, Lehigh County Extension Office Staff, and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613.