on infected plants, and high concentrations of sodium are harmful to plants. Potassium bicarbonate is an effective low-toxicity fungicide against powdery mildew and apple scab. Another non-conventional chemical treatment involves treating with a solution of calcium silicate. Silicon helps the plant cells defend against fungal attack by degrading haustoria and by producing callose and papilla. With silicon treatment, epidermal cells of wheat are less susceptible to powdery mildew. Genetic resistance The Pm3 allele is an effective genetic resistance strategy that protects host species against powdery mildew fungus. Gene editing In 2014, researchers Yanpeng Wang et al. have reported that they were able to induce resistance in hexaploid bread wheat to powdery mildew via targeted mutations with the use of CRISPR and TALENS gene-editing technology. Powdery mildews of various plants Sunflowers Sunflower powdery mildew is a disease caused by the pathogens Golovinomyces cichoracearum, Podosphaera xanthii, and Leviellula taurica. The symptoms caused by L. taurica differ from the other pathogen symptoms. Green-yellow spots appear on upper leaf surface. Wheat, barley and other cereals Blumeria graminis f. sp. tritici, causes powdery mildew of wheat, whereas f. sp. hordei causes powdery mildew of barley. Legumes Legumes, such as soybeans, are affected by Microsphaera diffusa. Grape Erysiphe necator (or Uncinula necator) causes powdery mildew of grapes. Onions The fungus causing powdery mildew of onions is Leveillula taurica (also known by its anamorph name, Oidiopsis taurica). It also infects the artichoke. Apples and pears Podosphaera leucotricha is a fungus that can cause powdery mildew of apples and pears. Gourds and melons Multiple species of fungus can cause powdery mildew of cucurbits: cucumbers, squashes (including pumpkins), luffas, melons, and watermelons. Podosphaera xanthii (a.k.a. Sphaerotheca fuliginea) is the most commonly reported cause on cucurbits. Erysiphe cichoracearum was formerly reported to be the primary causal organism throughout most of the world. Since 1925, commercial Cucumis melo (cantaloup and muskmelon) production has been engaged in a biological "arms race" against cucurbit powdery mildew (CPM) caused by the fungus Podosphaera xanthii, with new cultivars of melons being developed for resistance to successively arising races of the fungus, identified simply as race 1, race 2, etc. (seven in total by 2004), for races found around the world, and race N1 through N4 for some divergent races native to Japan. Various subraces have been identified, and given names such as race 2U.S., race 3.5, and race 4.5. A new race S was discovered