Native parasitoids of Dalbulus elimatus and Dalbulus maidis (Hemiptera: Cicadellidae) in winter crops of central Mexico

2007 ◽  
Vol 139 (5) ◽  
pp. 722-727 ◽  
Author(s):  
Gustavo Moya-Raygoza
Keyword(s):  
Zea Mays ◽  
Hordeum Vulgare ◽  
Annual Cycle ◽  
Winter Season ◽  
Central Mexico ◽  
Dalbulus Maidis ◽  
First Report ◽  
Native Parasitoids ◽  
Winter Crops ◽  
Corn Leafhopper

AbstractNative parasitoids of the adult Mexican corn leafhopper, Dalbulus elimatus (Ball), and corn leafhopper, Dalbulus maidis (Delong and Wolcott), are described and their rates of parasitism on maize, Zea mays L., common barley, Hordeum vulgare L., and sorghum, Sorghumbicolor (L.) Moench (Poaceae) in central Mexico are determined. The survey was conducted throughout an annual cycle, with sampling of the previous season's crops when they were available. Leafhoppers showing evidence of parasitism were reared individually in the laboratory to obtain adult parasitoids. Adult D. elimatus were parasitized on winter maize, barley, and sorghum by the fly Eudorylas subopacus (Loew) (Diptera: Pipunculidae) and the wasp Gonatopus bartletti Olmi (Hymenoptera: Dryinidae), whereas adult D. maidis were parasitized by these fly and wasp parasitoids on winter maize only. The highest rates of parasitism of D. elimatus by E. subopacus were 57.4% on maize, 39.6% on barley, and 48.8% on sorghum. The highest rate of parasitism of D. maidis by E. subopacus was 20.4% on maize. In contrast, the highest rates of parasitism of D. elimatus by G. bartletti were 9.4% on maize, 2.7% on barley, and 25.8% on sorghum. The highest rate of parasitism of D. maidis by G. bartletti was 7.1% on maize. These results indicate that winter crops are habitats of E. subopacus and G. bartletti during the winter season. This is the first report of D. elimatus and D. maidis being parasitized by E. subopacus and of D. elimatus being parasitized by G. bartletti.

EUDORYLAS (METADORYLAS) SP. (DIPTERA: PIPUNCULIDAE): A PREVIOUSLY UNREPORTED PARASITOID OF DALBULUS MAIDIS (DELONG AND WOLCOTT) AND DALBULUS ELIMATUS (BALL) (HOMOPTERA: CICADELLIDAE)

1991 ◽  
Vol 123 (1) ◽  
pp. 241-242 ◽  
Author(s):  
Fernando E. Vega ◽  
Pedro Barbosa ◽  
Alejandro Perez Panduro
Keyword(s):  
Latin America ◽  
Natural Enemies ◽  
Central Mexico ◽  
Dalbulus Maidis ◽  
Spiroplasma Kunkelii ◽  
Corn Stunt ◽  
Corn Stunt Spiroplasma ◽  
Maize Rayado Fino Virus ◽  
Corn Leafhopper

The genus Dalbulus (Homoptera: Cicadellidae) consists of 11 species, 10 of which can be found in México (Nault 1990). Some members in the genus, such as the corn leafhopper, Dalbulus maidis (DeLong and Wolcott), and the Mexican corn leafhopper, Dalbulus elimatus (Ball) are serious pests of maize due to their transmission of three corn stunting pathogens: corn stunt spiroplasma (CSS; Spiroplasma kunkelii Whitcomb et al.), maize bushy stunt mycoplasmalike organism (MBSM), and maize rayado fino virus (MRFV) (Nault 1990). Due to the widespread damage that these leafhopper-vectored pathogens cause in maize-growing regions in Latin America, a search for the leafhopper natural enemies was conducted in maize agroecosystems in central México.

Ultrastructure of Plant Leaf Tissue Infected with Mite-Borne Viral-Like Pathogens

1970 ◽  
Vol 28 ◽  
pp. 178-179 ◽  
Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault
Keyword(s):  
Triticum Aestivum ◽  
Zea Mays ◽  
Electron Microscope ◽  
Hordeum Vulgare ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Leaf Tissue ◽  
Leaf Ultrastructure ◽  
Double Membrane ◽  
Aceria Tulipae

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).

scholarly journals Yearly evolution of Euro-Atlantic weather regimes and of their sub-seasonal predictability

2021 ◽  
Author(s):  
Nicola Cortesi ◽  
Verónica Torralba ◽  
Llorenó Lledó ◽  
Andrea Manrique-Suñén ◽  
Nube Gonzalez-Reviriego ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Winter Season ◽  
Skill Score ◽  
Seasonal Forecast ◽  
Forecast Skill ◽  
Seasonal Forecasts ◽  
Sea Level Pressure ◽  
Weather Regimes ◽  
Start Dates ◽  
Weekly Frequency

AbstractIt is often assumed that weather regimes adequately characterize atmospheric circulation variability. However, regime classifications spanning many months and with a low number of regimes may not satisfy this assumption. The first aim of this study is to test such hypothesis for the Euro-Atlantic region. The second one is to extend the assessment of sub-seasonal forecast skill in predicting the frequencies of occurrence of the regimes beyond the winter season. Two regime classifications of four regimes each were obtained from sea level pressure anomalies clustered from October to March and from April to September respectively. Their spatial patterns were compared with those representing the annual cycle. Results highlight that the two regime classifications are able to reproduce most part of the patterns of the annual cycle, except during the transition weeks between the two periods, when patterns of the annual cycle resembling Atlantic Low regime are not also observed in any of the two classifications. Forecast skill of Atlantic Low was found to be similar to that of NAO+, the regime replacing Atlantic Low in the two classifications. Thus, although clustering yearly circulation data in two periods of 6 months each introduces a few deviations from the annual cycle of the regime patterns, it does not negatively affect sub-seasonal forecast skill. Beyond the winter season and the first ten forecast days, sub-seasonal forecasts of ECMWF are still able to achieve weekly frequency correlations of r = 0.5 for some regimes and start dates, including summer ones. ECMWF forecasts beat climatological forecasts in case of long-lasting regime events, and when measured by the fair continuous ranked probability skill score, but not when measured by the Brier skill score. Thus, more efforts have to be done yet in order to achieve minimum skill necessary to develop forecast products based on weather regimes outside winter season.

scholarly journals Geographic Distribution of Ryegrass Resistent to the Clethodim Herbicide in Rio Grande do Sul1

2016 ◽  
Vol 34 (2) ◽  
pp. 365-376
Author(s):  
L. VARGAS ◽  
T. SCHNEIDER ◽  
D. AGOSTINETTO ◽  
M.A. BIANCHI
Keyword(s):  
Geographic Distribution ◽  
Annual Cycle ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Action Mechanism ◽  
The North ◽  
Winter Crops ◽  
Glyphosate Herbicide ◽  
Continuous Use ◽  
Selection Of

ABSTRACT Ryegrass is a weed of annual cycle that is present in winter crops, in orchards and vineyards of the South region of Brazil. The species is normally controlled by the glyphosate herbicide, but the continuous use of this product caused the selection of resistant biotypes. The use of ACCase inhibitor herbicides is the main alternative for the control of this species, but it has not been satisfactory in some places, thus causing suspicion of resistance to this action mechanism. Thus, the objective of this paper was to evaluate the occurrence and geographic distribution of ryegrass biotypes that are resistant to the clethodim herbicide in the state of Rio Grande do Sul. For that, seeds of ryegrass plants that survived the application of clethodim were collected in crops from the north region of RS, summing up to a total of 152 samples from 72 cities. The biotypes were submitted to the application of 120 g i.a. ha-1 (maximum registered dose) and 60 g i.a. ha-1 de clethodim (half the maximum registered dose). According to the results, among the samples of ryegrass seeds collected, there were no biotypes resistant to the clethodim herbicide when the maximum registered dose was applied and in the stage of three to four leaves. However, there were biotypes with lower susceptibility that survived half the maximum registered dose.

scholarly journals First Report of Ophiosphaerella korrae Causing Root Rot of Hordeum vulgare in Korea

Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 158
Author(s):  
S. K. Hong ◽  
H.-W. Choi ◽  
Y. K. Lee ◽  
H.-H. Ham
Keyword(s):  
Hordeum Vulgare ◽  
Root Rot ◽  
First Report ◽  
Ophiosphaerella Korrae

scholarly journals Habitat of the Corn Leafhopper (Hemiptera: Cicadellidae) During the Dry (Winter) Season in Mexico

2007 ◽  
Vol 36 (5) ◽  
pp. 1066-1072 ◽  
Author(s):  
Gustavo Moya-Raygoza ◽  
Saskia A. Hogenhout ◽  
Lowell R. Nault
Keyword(s):  
Winter Season ◽  
Corn Leafhopper

Weed Control and Rotational Crop Response with AC 222,293

1987 ◽  
Vol 1 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Stephen D. Miller ◽  
Harold P. Alley
Keyword(s):  
Zea Mays ◽  
Hordeum Vulgare ◽  
Phaseolus Vulgaris ◽  
Avena Fatua ◽  
Crop Response ◽  
Leaf Stage ◽  
Wild Oats ◽  
Helianthus Annus ◽  
Rotational Crop ◽  
Pinto Beans

In the field, eight barley (Hordeum vulgare L.) cultivars tolerated postemergence applications of AC 222,293 [a mixture of methyl 6 and 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl) m- and p-toluate] at 0.4 to 1.4 kg/ha. AC 222,293 at 0.4 kg ai/ha applied at the 1.5- to 2-leaf stage controlled wild oats (Avena fatua L. # AVEFA) 96%, whereas 0.7 kg/ha applied at the 3.5- to 4-leaf stage controlled wild oats only 93%. Sugarbeets (Beta vulgaris L.) but not alfalfa (Medicago sativa L.), corn (Zea mays L.), pinto beans (Phaseolus vulgaris L.), or sunflower (Helianthus annus L.), were injured when planted 6 to 8 months after fall applications of AC 222,293 at 0.4 to 1.1 kg/ha.

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