Characterization of Species Associated with Stemphylium Leaf Spot of Spinach ().

Stemphylium leaf spot can result in significant losses to spinach seed, processing, and fresh market crops. isolates ( = 1,775) collected from 2000 to 2022 from spinach seed, leaves, and seed crop stem residues were used to assess the diversity of species associated with spinach. Eleven species were identified based on sequences: (63.

Prevalence of FRAC Group 11 Fungicide Resistance in Isolates, but Not Isolates, Causing Stemphylium Leaf Spot of Spinach ().

Stemphylium leaf spot of spinach, caused by and , is a disease of economic importance in fresh market, processing, and seed production. There have been increasing reports of difficulty managing the disease in the southern United States using fungicides in Fungicide Resistance Action Committee (FRAC) group 11. Isolates of and obtained from spinach leaves and seed from 2001 to 2020 were screened for resistance to azoxystrobin and pyraclostrobin in vitro, in vivo, and using PCR assays to detect mutations in associated with resistance in other fungi (F129L, G137R, and G143A).

Gall-Insect Community on Big Sagebrush Varies With Plant Size but not Plant Age.

There is astounding variation in the abundance and diversity of insect herbivores among plant individuals within plant species in natural systems. One of the most well studied hypotheses for this pattern, the plant architecture hypothesis, suggests that insect community patterns vary with plant structural complexity and plant traits associated with structure. An important limitation to our understanding of the plant architecture hypothesis has been that most studies on the topic confound plant size and plant age.