Field resistance to Benomyl in Cucurbit powdery mildew.

1973 ◽  
Vol 2 (4) ◽  
pp. 27 ◽  
Author(s):  
RA Peterson
Author(s):  
O. O. Kalinina ◽  
O. D. Golyaeva ◽  
O. V. Panfilova ◽  
А. V. Pikunova

Powdery mildew is one of the most harmful fungal diseases that causes economically significant damage to berry plantations. The disease is common in all areas of currant cultivation in the Russian Federation. In this regard, in modern conditions of intensive berry growing, the problem of breeding cultivars that are highly resistant to diseases and pests becomes urgent. Breeders have a difficult task to combine the adaptive potential of the cultivar with its annual high productivity and resistance to biotic environmental factors. When studying the adaptability of introduced cultivars of red currant and selected forms of the Institute to local soil and climate conditions, the following cultivars were identified as sources of economic and useful characteristics and involved in selection: ‘Belaya Potapenko’ as a complex source of resistance powdery mildew and high marketable and taste qualities of berries; SS 1426-21-80 as a source of high productivity and long racemes (raceme length 11-13 cm; up to 20 berries in the raceme). On their base the selection family of red currant has been developed: Belaya Potapenko × ♂SS 1426-21-80. The study of data on the destruction of hybrid seedlings of the selection family by powdery mildew showed that in epiphytotic conditions, the percentage of intensity of the disease development varies over the periods of screening from 0.2% in May to 20.4% in June. Such indicators served as a prerequisite for conducting a comparative test of breeding material in the field under artificial infection with powdery mildew. After artificial infection on the background of epiphytosis, the rate of intensity of the disease development increased slightly and amounted to 35.6% for the family. There were 30 highly resistant seedlings in the family, 10 of which have remained stable and highly resistant since 2018. In these plants we can assume the presence of the so-called field resistance, controlled by polygens, each of which does not give a visible effect of stability, but with different combinations determines one or another of its degree. Highly resistant seedlings will be used in further breeding studies to identify new sources of resistance to powdery mildew.


2016 ◽  
Vol 213 (4) ◽  
pp. 1961-1973 ◽  
Author(s):  
Jesús Martínez‐Cruz ◽  
Diego Romero ◽  
Antonio Vicente ◽  
Alejandro Pérez‐García

2018 ◽  
Vol 19 (3) ◽  
pp. 220-221 ◽  
Author(s):  
Anthony P. Keinath ◽  
Gabriel Rennberger ◽  
Chandrasekar S. Kousik

Resistance to boscalid, one of the older succinate-dehydrogenase inhibitors (SHDI) in Fungicide Resistance Action Committee (FRAC) code 7, was detected in Podosphaera xanthii, the cucurbit powdery mildew fungus, in South Carolina in July 2017. Resistance to the field rate (682 ppm) of boscalid was confirmed in greenhouse experiments and laboratory bioassays conducted on summer squash plants and cotyledons, respectively, that had been treated with a range of boscalid concentrations. This report is the first documentation of resistance to boscalid in P. xanthii in the southern United States.


Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1515-1524 ◽  
Author(s):  
Alejandra Vielba-Fernández ◽  
Antonio de Vicente ◽  
Alejandro Pérez-García ◽  
Dolores Fernández-Ortuño

Powdery mildew, caused by the fungus Podosphaera xanthii, is one of the most economically important diseases affecting cucurbit crops in Spain. Currently, chemical control offers the most efficient management of the disease; however, P. xanthii isolates resistant to multiple classes of site-specific fungicides have been reported in the Spanish cucurbit powdery mildew population. In previous studies, resistance to the fungicides known as methyl benzimidazole carbamates (MBCs) was found to be caused by the amino acid substitution E198A on β-tubulin. To detect MBC-resistant isolates in a faster, more efficient, and more specific way than the traditional methods used to date, a loop-mediated isothermal amplification (LAMP) system was developed. In this study, three sets of LAMP primers were designed. One set was designed for the detection of the wild-type allele and two sets were designed for the E198A amino acid change. Positive results were only obtained with both mutant sets; however, LAMP reaction conditions were only optimized with primer set 2, which was selected for optimal detection of the E198A amino acid change in P. xanthii-resistant isolates, along with the optimal temperature and duration parameters of 65°C for 75 min, respectively. The hydroxynaphthol blue (HNB) metal indicator was used for quick visualization of results through the color change from violet to sky blue when the amplification was positive. HNB was added before the amplification to avoid opening the lids, thus decreasing the probability of contamination. To confirm that the amplified product corresponded to the β-tubulin gene, the LAMP product was digested with the enzyme LweI and sequenced. Our results show that the LAMP technique is a specific and reproducible method that could be used for monitoring MBC resistance of P. xanthii directly in the field.


2004 ◽  
Vol 99 (3-4) ◽  
pp. 257-265 ◽  
Author(s):  
E Křı́stková ◽  
A Lebeda ◽  
B Sedláková

Sign in / Sign up

Export Citation Format

Share Document