Also called “penetrants,” systemic fungicides work by becoming absorbed into the plant tissues and protecting the plant from fungal diseases as well as ridding the plant of any existing diseases. Some systemic fungicides are locally systemic, meaning that the chemicals aren’t transmitted very far from the application site on the plant. Other systemic fungicides are applied to and absorbed up through the roots, moving throughout the rest of the plant.
Myclobutanil is a systemic fungicide that controls fungal diseases like powdery mildew, fungal leaf spots, rusts and anthracnose on many different kinds of flowers, shrubs and trees. Specifically, myclobutanil controls powdery mildew, scab and rust on apple trees; brown rot, powdery mildew and blossom blight on stone fruits like peaches; and powdery mildew and black rot on grapes. Myclobutanil is currently part of commercial fungicide products like Spectracide Immunox, Green Light Fung-Away, Nova, Ferti-lome F-Stop and some other granular products. To control scab on apple trees, mix myclobutanil with a broad-spectrum contact fungicide containing mancozeb and captan.
Fenbuconazole controls brown rot blossom blight and fruit rot on peaches, as well as scab and cherry leaf spot. This systemic fungicide also controls powdery mildew on sour cherry trees. The trade name for fenbuconazole is Indar.
Sold under the trade names Orbit and Ferti-lome Liquid Systemic Fungicide, propiconazole is registered to control brown rot blossom blight and fruit rot on cherry, peach and plum trees. Propiconazole is a water-based systemic fungicide that’s also effective at treating most other major fungal diseases in trees, shrubs, flowers and lawns.
Triflumizole controls powdery mildew and scab on pears and apples with a similar action as myclobutanil. Triflumizole systemic fungicide is sold commercially as Procure.
Also similar to myclobutanil is fenarimol, a systemic fungicide that controls powdery mildew and scab on apple and pear trees. Fenarimol is also labeled to control rust on apple trees, as well as powdery mildew and cherry leaf spot on cherry trees. Sold under the brand name Rubigan, fenarimol can be mixed with the contact fungicide captan or mancozeb to increase its effectiveness against scab disease. Fenarimol isn’t effective at controlling brown rot, and it’s only effective when used at a rate of at least 2 fluid oz. per 100 gallons of water.
Labeled to control fruit rot and powdery mildew on cherry, peach and plum trees, tebuconazole also treats brown rot blossom blight and cherry leaf spot diseases. Tebuconazole is a systemic fungicide sold for use on fruit trees under the brand name Elite.
Triadimefon is a systemic fungicide that’s sold under several brand names, but only Bayleton 50% DF is labeled for use on fruit trees. Specifically, triadimefon is effective at controlling cedar apple rust and powdery mildew on apple trees, as well as powdery mildew on pear trees.