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Weed resistance to acetohydroxyacid synthase (AHAS) inhibiting herbicides has been a critical issue for rice growers worldwide since the early 1990's. In California, resistance to bensulfuron-methyl was first detected in Cyperus difformis in 1993. Since then, populations of most major weeds of rice in California have been reported to show resistance to at least one AHAS inhibitor. We sought to describe the magnitude and mechanisms of AHAS inhibitor cross-resistance in California populations of C. difformis. Sixty-two populations were collected and screened for cross-resistance to bensulfuron-methyl (BEN), halosulfuron-methyl (HAL), bispyribac‑sodium (BIS), and penoxsulam (PEN), revealing six major patterns of cross-resistance. Representative C. difformis populations from each cross-resistance pattern were then subjected to dose-response, cytochrome P450 inhibition, AHAS gene sequencing, and metabolic studies with the same herbicides as in the screening. Dose-response confirmed the detected resistances in the representative populations, and suggested that the majority of observed resistance was dose-dependent. Cytochrome P450 inhibition via malathion revealed evidence of increased metabolic activity in resistant populations to BEN, BIS, and PEN. AHAS gene sequencing revealed amino acid substitutions in five of six populations: R3 (Pro197-Ser), R4 (Pro97-His), R10 (Asp376), R41 (Ala122-Asn), and R18 (Trp574-Leu). Metabolic studies confirmed evidence of increased activity of cytochrome P450s in all populations. Metabolic BEN and HAL analysis did not yield similar results to malathion inhibition, suggesting different P450's or other pathways. Taken together, the results of the studies confirm the complexity of AHAS inhibitor cross-resistance in C. difformis , and the presence of both target-site and metabolic resistance in most of the representative populations underscores the importance of proper herbicide selection, rotation, and scouting in fields. [Display omitted] • AHAS inhibitor cross-resistance is a common and serious issue in agriculture. • Cyperus difformis populations cross-resistant to AHAS inhibitors are found worldwide. • California C. difformis populations were found to have several AHAS mutations conferring resistance. • Evidence of increased cytochrome P450, GST, GT activity also was detected. [ABSTRACT FROM AUTHOR]

Rice grown in the Sacramento Valley of California is predominantly water seeded (WS), by direct-seeding rice into flooded basins. The effects of flooded rice monoculture and limited herbicides have led to difficult-to-control weed populations, and widespread local herbicide resistance. A novel "stale-drill" rice establishment method has been under investigation in California, to address these constraints. Two rice varieties with high seedling vigor ('M-206', 'M-209') were dry-drilled to 3 cm and 6 cm in 2018 and 2019, and fields were flush-irrigated to initiate weed germination prior to stand emergence. A postplant-burndown (PPB) application of glyphosate at 870 g a.e. ha-1 was applied 6-7 days after planting (DAP), at rice emergence, which controlled >50% of total seasonal weeds. Glyphosate PPB caused rice first-leaf dieback, but no other symptoms developed. Planting depth or cultivar did not affect date of emergence either year. Deeper seeding reduced M-206 and M-209 stands by 15.4% and 5.2%, respectively, in 2018, but not in 2019. Increased tillering compensated for stand reductions in 2018. Panicle yield components were largely unaffected by planting depth in 2018, however florets panicle-1 and filled grains panicle-1 were slightly greater for both cultivars at 6 cm. In 2019, M-209 suffered reductions in florets per panicle and grain filling at 6 cm planting depth. Grain yields were unaffected by planting depth in either study year. M-206 and M-209 grain yields were 10.2 T ha-1 and 12.2 T ha-1 respectively, in 2018, and 9.4 T ha-1 and 9.1 T ha-1 respectively, in 2019. Proper water management and scouting are essential to ensure that PPB treatments do not injure emerging rice to the extent that weak or reduced stands result. However, the present study serves as a promising proof-of-concept for the "stale-drill" method as an alternative stand establishment method in mechanized rice production. [ABSTRACT FROM AUTHOR]

In the middle of a pandemic, patients with cough and fever are thought to have SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). It should be remembered that in the desert southwest of the United States, we have an ongoing epidemic of coccidioidomycosis (CM). There are additionally many other respiratory illnesses that could be confused with CoV-2 or overlooked. This is a case report of CoV-2 engrafted on chronic cavitary pulmonary CM. In a time where the coronavirus pandemic is becoming rampant, we demonstrate the case of a coinfection with cavitary pulmonary CM. In this case, the importance of detection of the coronavirus and treatment of the coinfection is explored.