scholarly journals Seedling disease of corn caused by Pythium increases with proximity of rye

Plant Disease ◽  
2020 ◽  
Author(s):  
Sarah Maria Kurtz ◽  
Jyotsna Acharya ◽  
Thomas C. Kaspar ◽  
Alison E Robertson

Yield loss of corn following a winter rye cover crop (CC) has been associated with increases seedling disease caused by Pythium spp. We hypothesized that physical separation between the CC and corn could reduce the risk of seedling disease, and benefit corn growth and development. In a growth chamber experiment, corn seedlings were planted at 0 cm and 8-10 cm, from terminated winter rye plants. Root rot severity was assessed at crop development stage V2, and quantitative PCR was used to estimate the abundance of Pythium clade B and clade F members present in corn roots. Radicle and seminal root rot severity was numerically greater when seedlings were planted 0 cm from terminated rye plants compared to seedlings planted 8-10 cm away. Moreover, a greater abundance of Pythium clade B was detected in corn grown within the terminated winter rye compared to corn planted further away (P = 0.0003). No effect of distance between corn and winter rye was detected for Pythium clade F. These data contribute to our understanding of the effect of a winter rye cover crop on corn and will inform field trial management practices for farmers to reduce occasional yield loss of corn following a winter rye cover crop.

Plant Disease ◽  
2021 ◽  
Author(s):  
Sarah Maria Kurtz ◽  
Jyotsna Acharya ◽  
Thomas C. Kaspar ◽  
Alison E Robertson

Despite numerous environmental benefits associated with cover crop (CC) use, some farmers are reluctant to include CCs in their production systems because of reported yield declines in corn. There are numerous potential reasons for this yield decline, including seedling disease. A winter rye CC can serve as a ‘green bridge’ for corn seedling pathogens. We hypothesized that proximity of corn seedling roots to decaying rye CC roots contributes to corn seeding disease. An experimental field plot and an on-farm study were conducted over two years to evaluate growth, development, and disease severity of corn seedlings planted at various distances from decaying winter rye CC plants. The experimental field plot study was conducted in a no-till corn-soybean rotation with five replications of a winter rye CC treatments seeded as (i) no CC control, (ii) broadcast, (iii) 19-cm drilled rows, and (iv) 76-cm drilled rows. The on-farm study was no-till corn-soybean rotation with four replications of a winter rye cover crop seeded as 38-cm drilled rows, 76-cm drilled rows, and no CC control. The corn was planted on 76-cm rows shortly after rye was terminated. With multiple seeding arrangements of winter rye, corn was planted at different distances from winter rye. Corn radicle root rot severity and incidence, shoot height, shoot dry weight, corn height and chlorophyll at VT, ear parameters, and yield were collected. Soil samples were taken in the corn row and the interrow at winter rye termination, corn planting, and corn growth stage V3 to estimate the abundance of Pythium clade B members present in soil samples. Our results showed that increased distance between winter rye residue and corn reduced seedling disease and Pythium clade B populations in the radicles and soil, and increased shoot dry weight, leaf chlorophyll, plant height, and yield. This suggests that physically distancing the corn crop from the winter rye CC is one way to reduce the negative effects of a winter rye CC on corn.


Plant Disease ◽  
2017 ◽  
Vol 101 (4) ◽  
pp. 591-600 ◽  
Author(s):  
J. Acharya ◽  
M. G. Bakker ◽  
T. B. Moorman ◽  
T. C. Kaspar ◽  
A. W. Lenssen ◽  
...  

Experiments were established in a controlled-growth chamber and in the field to evaluate the effect of the length of time intervals between winter rye cover crop termination and corn planting on corn seedling disease, corn growth, and grain yield in 2014 and 2015. Rye termination dates ranged from 25 days before planting (DBP) to 2 days after planting (DAP) corn in the field and from 21 DBP to 1 DAP in controlled studies. Results were similar in both environments. In general, shorter intervals increased seedling disease and reduced corn emergence, shoot growth, and grain yield of corn following winter rye compared with corn planted 10 or more days after rye termination or without rye. Incidence of Pythium spp. increased with shorter intervals (less than 8 DBP); incidence of Fusarium spp. was not consistent between runs and experiments. In 2014, in the 1-DAP treatment, number of ears and grain yield were reduced (P = 0.05 and 0.02, respectively). In 2015, all termination intervals reduced plant population, number of ears, and yield (P = 0.01), with the 2-DBP treatment causing the biggest decrease. A 10- to 14-day interval between rye termination and corn planting should be followed to improve corn yield following a rye cover crop.


Author(s):  
John E. Sawyer ◽  
Jose L. Pantoja ◽  
Daniel W. Barker

Author(s):  
John E. Sawyer ◽  
Jose L. Pantoja ◽  
Daniel W. Barker

Author(s):  
John E. Sawyer ◽  
Jose L. Pantoja ◽  
Daniel W. Barker

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 220
Author(s):  
Jo Marie Reiff ◽  
Sebastian Kolb ◽  
Martin H. Entling ◽  
Thomas Herndl ◽  
Stefan Möth ◽  
...  

Habitat simplification and intensive use of pesticides are main drivers of global arthropod declines and are, thus, decreasing natural pest control. Organic farming, complex landscapes, and local vineyard management practices such as implementation of flower-rich cover-crop mixtures may be a promising approach to enhance predator abundance and, therefore, natural pest control. We examined the effect of organic versus integrated management, cover-crop diversity in the vineyard inter-rows, and landscape composition on the natural pest control of Lobesia botrana eggs and pupae. Predation of L. botrana pupae was reduced by organic farming and species-poor cover-crops by about 10%. Predation rates of L. botrana eggs did not differ significantly in any of the studied management options. Dominant predators were earwigs (Forficulidae), bush crickets (Tettigoniidae), and ants (Formicidae). Negative effects of organic viticulture are most likely related to the negative nontarget effects on arthropods related to the frequent sulfur and copper applications in combination with the avoidance of strongly damaging insecticides by integrated winegrowers. While a 10% difference in predation rates on a single pest stage is unlikely to have strong practical implications, our results show that the assumed effectiveness of environmentally friendly agriculture needs to be evaluated for specific crops and regions.


Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 441
Author(s):  
Hans J. Kandel ◽  
Dulan P. Samarappuli ◽  
Kory L. Johnson ◽  
Marisol T. Berti

Adoption of cover crop interseeding in the northwestern Corn Belt in the USA is limited due to inadequate fall moisture for establishment, short growing season, additional costs, and need for adapted winter-hardy species. This study evaluated three cover crop treatments—no cover crop, winter rye (Secale cereale L.), and winter camelina (Camelina sativa (L.) Crantz)—which were interseeded at the R6 soybean growth stage, using two different soybean (Glycine max (L.) Merr.) maturity groups (0.5 vs. 0.9) and two row spacings (30.5 vs. 61 cm). The objective was to evaluate these treatments on cover crop biomass, soil cover, plant density, and soybean yield. Spring wheat (Triticum aestivum L.) grain yield was also measured the following year. The early-maturing soybean cultivar (0.5 maturity) resulted in increased cover crop biomass and soil cover, with winter rye outperforming winter camelina. However, the early-maturing soybean yielded 2308 kg·ha−1, significantly less compared with the later maturing cultivar (2445 kg·ha−1). Narrow row spacing had higher soybean yield, but row spacing did not affect cover crop growth. Spring wheat should not follow winter rye if rye is terminated right before seeding the wheat. However, wheat planted after winter camelina was no different than when no cover crop was interseeded in soybean. Interseeding cover crops into established soybean is possible, however, cover crop biomass accumulation and soil cover are limited.


2021 ◽  
Author(s):  
Harry H. Schomberg ◽  
Dinku M. Endale ◽  
Kipling S. Balkcom ◽  
Randy L. Raper ◽  
Dwight H. Seman
Keyword(s):  

1999 ◽  
Vol 26 (2) ◽  
pp. 80-84
Author(s):  
J. E. Hollowell ◽  
B. B. Shew ◽  
M. K. Beute

Abstract Thirteen isolates of Cylindrocladium parasiticum Crous, Wingfield & Alfenas from North Carolina and 11 from Georgia were grown on plates of PDA at 20,25, and 30 C on a temperature-gradient plate. Culture diameters were measured daily for 6 d. Significant differences were not observed among isolates grown at 20 C and cultures was smaller as compared with those grown at 25 and 30 C. At 25 and 30 C, isolates varied consistently in growth. On average, Georgia isolates grew slightly less than North Carolina isolates, and all isolates grew better at the warmer temperature. Growth of three North Carolina isolates was compared to four Florida isolates in a second experiment. Florida isolates grew significantly faster than North Carolina isolates at all temperatures. Isolates from the three states were compared for their ability to cause root rotting on peanut at 25 and 30 C. Plants were grown in soil infested at a standardized inoculum density in temperature-controlled water bath tanks for 7 wk at which time roots were rated for Cylindrocladium black rot development. Georgia isolates caused more root rot than either North Carolina or Florida isolates at both temperatures and also caused more seedling disease. State effects were significant; Florida isolates caused less root rot than Georgia isolates. Temperature by state interactions were not significant which means that high temperature-tolerant isolates of C. parasiticum have not evolved from regional differences in soil temperature. Further, North Carolina field isolates do not appear to have changed in temperature optima since the 1970s.


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