We're excited! The U of I Coles County Extension Master Gardeners are putting together a "Spring into Gardening" conference which will be open to the public. We are still finalizing details, but we can tell you there will be some fantastic speakers, door prizes, a silent auction and yummy refreshments. So put the morning of Saturday, February 28 on your calendar and stay tuned for further details in these Saturday columns!

Winter cleanup will help prevent plant diseases next year. Practice good hygiene: Disinfect your tools with a 10% bleach solution, and then burn the cuttings to avoid spreading the disease. If local ordinances prohibit burning, burying them is called for. Don't take them to the wonderful landscape recycling sites in Charleston and Mattoon. You'll be passing along the disease to an innocent user of the mulch produced by the site.

Aster yellows

Identification — Hundreds of different plants are susceptible, including aster, zinnia, coneflower, cannas, carrot, lettuce, tomato and many others. Weeds, such as dandelion, thistle and plantain, can also carry this persistent disease. Deformed flowers, yellow foliage and stunted growth are classic signs of this disease. Though symptoms vary according to the temperature and the age and type of plant, the first thing most gardeners notice is green, twisted flowers with clusters of extra leaf growth in the center. However, if you're really paying attention, yellowing of new leaves, including the veins, usually happens first. (If the veins remain green, the plant probably has a nutrient deficiency). Growth may also be lopsided, with one side of the plant looking normal while the other side is stunted.

Damage — Aster yellows is caused by a tiny phytoplasma, an organism smaller than a bacteria but larger than a virus, that infects the food-conducting cells of the plant.

The phytoplasma is carried from plant to plant by hungry leafhoppers, known as six-spotted leafhoppers (Macrosteles quanrilineatus). These tiny, winged insects live on the underside of leaves and feed on the sap, spreading the disease as they travel from plant to plant. Cool, wet summer weather favors both leaphopper and phytoplasma spread.

Control — There is no cure for aster yellows, but it rarely kills a plant outright. It's important to remove and destroy any infected ones. If you leave these plants in the garden, leafhoppers will continue to visit them and spread the disease. To prevent aster yellows, clear your garden of dead foliage and debris in late fall to eliminate overwintering sites for leafhopper adults and eggs. During the growing season you can also spray the tops and undersides of leaves with insecticidal soap or insecticides like pyrethrin or neem to get rid of leafhoppers.

Black knot fungus

Apiosporina morbosa

Identification – When the leaves are off the trees, these grotesque, black swellings are easy to spot. You'll find them mainly on members of the Prunus family — cherries, plums and peaches. They are fungus spores spread by wind, insects, birds or humans. Black knot grows in warm (55 to 75 degrees), humid spring weather. The swellings develop over a two-year period. Even though infection begins the first year, no real symptoms appear until the following spring. Then the bark on a stem splits and a green fungus appears. It could cover an area 12 inches long and be several times thicker than the branch it infects. This green fungus hardens and turns black and knotty.

Damage – These growths, or knots, shut off water and nutrients to the branch, which eventually wilts, dries up and dies.

Control – The best defense against black knot is to plant resistant varieties. Check with your extension service or nursery for recommendations. During the fall and winter, prune and destroy infected branches. Cut at least 4 inches below the swollen, black area. To prevent spreading, dip pruning tools in a 10-percent bleach solution between cuts.

Daylily rust

Identification — Like other rust diseases, daylily rust causes orange spots and streaks on the leaves. If you see suspicious spots, rub a tissue along the leaves — rust will leave an orange smear. Infected leaves will turn brown and die, but rust won't kill the plant.

Control — There are some resistant cultivars available, but even those aren't bullet-proof. To slow the spread, cut back, clean up and destroy infected foliage in the fall. Disinfect your hands and pruners between plants with a 10% bleach solution. During the growing season, avoid overhead watering and make sure plants have good air circulation.

If you noticed any of these symptoms this past year, be sure to follow the hygiene procedures mentioned above, then be on the lookout for the symptoms next spring … if it ever comes. Doesn't it already seem as though winter has been hanging around a long time?! However, when I become impatient for green, I hearken back to when I visited my sister in San Diego and admired her lush garden. She looked at me over the top of her glasses and sighed, "…but it NEVER stops growing." So winter does make us appreciate our growing season.

Now would be a good time to pencil in February 28 on your calendar.