Stigmatomycosis is a fungal disease that occurs in a number of crops, such as cotton, soybean, pecan, pomegranate, citrus, and pistachio.
In a 1989 survey in California, fruit with stigmatomycosis were found in 90% of samples collected from late June to mid-September and from all growing areas.
All of them belong to the phylum of ascomycetes[citation needed] The fungi causing stigmatomycosis are associated with hemipteran insects of the stinkbug families Pentatomidae and Coreidae.
Symptoms first appear in late June after pistachio shells have hardened, but the disease becomes frequent in July through September, a period that coincides with kernel development.
Smaller hemipterans, such as Lygus and Calocoris, may carry but not transmit the pathogens because they are unable to puncture the firm fruit pericarp after the second part of May.