to have fixed effects whereas the replications a random effect. Measurements. Measurements were taken when the susceptible check was completely dead. Leaf injury was assessed based on a 1 to 7 scale ( Fig. 3 ) (1 = healthy plants, 2 = first sign of
Waltram Ravelombola, Jun Qin, Yuejin Weng, Beiquan Mou, and Ainong Shi
A common practice in highbush blueberry (Vaccinium corymbosum L.) culture is to use combinations of insecticides and fungicides to reduce the number and cost of pesticide applications. In response to apparent phytotoxicity observed in commercial fields that were treated with combinations of diazinon and captan formulations, phytotoxicity of two formulations of diazinon (Diazinon AG600 and Diazinon 50W) and captan (Captan 80WP and Captec 4L) was investigated on highbush blueberries during 1997 and 1998. Phytotoxicity injury similar to injury observed in commercial fields was reproduced in treatments with diazinon and captan mixtures in all experiments. The Diazinon AG600 and Captec 4L mixture was the most severe and caused significantly more phytotoxic-ity to fruit and leaves than individual treatments of Diazinon AG600, Captec 4L or untreated control. Separation of diazinon and captan applications by 8 h significantly reduced phytotoxicity compared to mixture treatments. Injured fruit and leaves recovered over time and most treatments showed only a mild injury at the time of harvest. Phytotoxicity on fruit and leaves caused by Diazinon AG600 and Captec 4L mixture was significantly affected by application date with the earliest application causing the greatest injury. These data indicate that diazinon and captan mixtures cause phytotoxicity on highbush blueberries and therefore the two should not be applied in combination.
Qiansheng Li, Jianjun Chen, Robert H. Stamps, and Lawrence R. Parsons
. Table 1. A brief genetic background of the eight Dieffenbachia cultivars and their critical chilling temperatures and durations based on visual leaf injury. Plant canopy heights and widths were measured 5 months after potting. The growth
Youbin Zheng, Linping Wang, Diane Feliciano Cayanan, and Mike Dixon
Cu 2+ application, plant growth was significantly reduced by nutrient solutions with Cu 2+ concentration 1.05 mg·L −1 or greater ( Fig. 2 ). These results are consistent with visual leaf injury and SPAD results in which no Cu 2+ treatment effects
Thomas M. Kon, James R. Schupp, Keith S. Yoder, Leon D. Combs, and Melanie A. Schupp
combination of damaged floral tissue and reduced photosynthesis due to leaf injury. In some experiments, ATS caused unacceptable leaf phytotoxicity ( Byers, 1997 ; Embree and Foster, 1999 ), which resulted in reduced fruit growth ( Wertheim, 2000
Diane Feliciano Cayanan, Mike Dixon, Youbin Zheng, and Jennifer Llewellyn
chlorine in the water and potentially resulting in leaf injury. Nonetheless, many of the observed injuries were mild and difficult to detect. Our previous research ( Cayanan et al., 2008b ) indicated that a free chlorine concentration less than 2.5 mg·L −1
Genhua Niu, Denise S. Rodriguez, Lizzie Aguiniga, and Wayne Mackay
. Results After 11 weeks of treatment, L. havardii had leaf injuries at salinity levels 5.7 dS·m −1 or greater. The 7.6 dS·m −1 and 9.4 dS·m −1 salinity treatments had 7% and 0% survival rates, respectively. Plants had similar visual appearance and no
James D. Oster, D.E. Stottlmyer, and M.L. Arpaia
, were less than would be expected to cause leaf injury. There were no significant effects of the AW or F treatments on root length ( Fig. 4 ), or dry weight, in the 0- to 60-cm depth interval. Root length ( Fig. 4 ) decreased rapidly with depth: from
C.E. Gambrell Jr., D.C. Coston, and E.T. Sims Jr.
The ethylene-releasing agent CGA-15281 (2-chlorethyl-methylbis (phenylmethoxy) silane) effectively thinned fruit of several cultivars of peach [Prunus persica (L.) Batsch.]. Thinning varied with cultivar, stage of development, concentration, and application technique. Negligible (<1%) leaf injury and drop occurred even at the higher (720 ppm) concentration over the 8-year period.
Thomas Graham, Ping Zhang, Youbin Zheng, and Michael A. Dixon
pixel count. The LDI accounts for all damaged tissue, regardless of origin, so the differences evaluated are relative to the control, which was considered to be the baseline. Fig. 1. Representative steps in the image analysis used to quantify leaf injury