Question
what can I use to spray my apple and peach trees? they both have spot- like rust on the leaves. they are young trees only 4-6 feet tall.

Answer
Sounds like cedar apply rust. Cedar-Apple Rust on Apple: Pale yellow spots appear on the upper surface of leaves during May or June. Spots are up to l/4 inch in diameter, turn orange with time, and often have a reddish border. Small black fungal bodies (pycnia) form within the spots and may exude an orange fluid. In time, yellow spots develop on the underside of the leaf. These spots thicken, and during late spring and early summer, a number of small, orange-yellow tubular projections (aecia) appear. These develop into open, cylindrical tubes that split toward the base into narrow strips and curl backward. Infected leaves may turn yellow and drop. Defoliation of rusted leaves is most common in dry summers. On fruit, similar yellow-orange spots appear, usually at or near the calyx end. These spots usually occur on immature fruit and are much larger than the spots on leaves (up to 3/4 inch in diameter). The light green color of the young fruit becomes a darker green around the infected area. The tube-like aecia may form on the slightly raised fruit lesions. Infected fruits are often stunted and misshapen, and may drop early.

Several fungicides can be used to protect apples from cedar-apple rust. Triadimetone (Bayleton), ferbam (Carbamate), triforine (Funginex) and fenarimol (Rubigan) are all effective in controlling rust. The materials should be applied as sprays at seven to fourteen-day intervals starting at the pink stage of bud development up to the middle of June. Ferbam and fenarimol will also control apple scab. Check the fungicide label for information on rates and times of application.