Related Experiment Video
Updated: Jan 29, 2026
07:25
High-throughput Screening of Chemical Compounds to Elucidate Their Effects on Bacterial Persistence
Published on: February 23, 2021
4.5K
Persistence of Phenylamide Insensitivity in Pseudoperonospora humuli
David H Gent1, Mark E Nelson2, Gary G Grove2
1United States Department of Agriculture-Agricultural Research Service, Forage Seed and Cereal Research Unit, and Oregon State University, Department of Botany and Plant Pathology, Corvallis 97331.
Plant Disease
|February 17, 2019
Summary
Phenylamide fungicide insensitivity in hop downy mildew (Pseudoperonospora humuli) is prevalent in the northwestern US. Management strategies should shift away from these fungicides in affected regions.
Area of Science:
- Plant Pathology
- Fungal Genetics
- Agricultural Science
Background:
- Downy mildew, caused by Pseudoperonospora humuli, significantly impacts hop production.
- Phenylamide fungicides were once effective but insensitivity emerged in the 1990s.
Purpose of the Study:
- Quantify phenylamide fungicide insensitivity in Pseudoperonospora humuli isolates.
- Determine the prevalence of insensitivity in the northwestern United States from 2005-2007.
Main Methods:
- Leaf disk assays with discriminating doses of metalaxyl/mefenoxam.
- Inoculum from 201 systemically infected hop shoots (basal spikes).
- Dilution series assays to determine effective dose (ED50) for sporulation inhibition.
Main Results:
- Insensitivity to mefenoxam detected in 41.9% of basal spikes.
- Insensitivity to metalaxyl detected in 65% of basal spikes.
- ED50 values indicated a stable insensitivity phenotype in P. humuli.
Conclusions:
- Phenylamide fungicide insensitivity is widespread in northwestern US hop yards.
- Management of hop downy mildew must incorporate alternatives to phenylamide fungicides.
- Affected regions include Idaho, Oregon, and Washington.
Related Concept Videos
01:15Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
1.0K
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) is an advanced Nuclear Magnetic Resonance (NMR) technique specifically designed to detect and enhance the signals of low-abundance nuclei, such as carbon-13 and nitrogen-15, in small molecules. The fundamental principle behind INEPT is the transfer of polarization from a more abundant and highly polarizable nucleus, typically hydrogen-1, to the low-abundance nucleus of interest. This process effectively boosts the NMR signal of the...
1.0K
01:36Mismatch Repair
43.7K
Overview
43.7K
02:55Stereotypes, Prejudice, and Discrimination
95.4K
Humans are very diverse and although we share many similarities, we also have many differences. The social groups we belong to help form our identities (Tajfel, 1974). These differences may be difficult for some people to reconcile, which may lead to prejudice toward people who are different. Prejudice is a negative attitude and feeling toward an individual based solely on one’s membership in a particular social group (Allport, 1954; Brown, 2010). Prejudice is common against people who...
95.4K
02:36Electromotive Force
30.1K
Electricity is generated by either electrons or ions flowing through a solution or a conducting medium. This flow of electrons or specifically electrical charge is defined as an electric current. When electrons move through a wire, they generate an electric current. It can be recalled that in a redox reaction, electrons are lost and gained. In the spontaneous redox reaction of zinc with copper, when zinc is immersed in a copper ion solution, a transfer of electrons from one substance to...
30.1K
03:37Uncertainty in Measurement: Accuracy and Precision
100.9K
Scientists typically make repeated measurements of a quantity to ensure the quality of their findings and to evaluate both the precision and the accuracy of their results. Measurements are said to be precise if they yield very similar results when repeated in the same manner. A measurement is considered accurate if it yields a result that is very close to the true or the accepted value. Precise values agree with each other; accurate values agree with a true value.
100.9K
04:49Robbers Cave
14.8K
During the 1950s, the landmark Robbers Cave experiment demonstrated that when groups must compete with one another, intergroup conflict, hostility, and even violence may result. At the Oklahoman summer camp, two troops of boys—termed the Rattlers and the Eagles—took part in a week-long tournament. During this time, their negativity culminated in derogatory name-calling, fistfights, and even vandalism and destruction of property. However, this work also revealed that such tension...
14.8K