Page 56 - Free State Spring 2023_WEB

TOTAL PLANT MANAGEMENT (Continued)

Resistance is a wonderful tool, but it is not immunity plants of each cultivar. Plants were planted in raised beds
from a disease. Weather varies from location to location made up of 8% leaf compost, and a trickle irrigation
and year to year, which influences the disease pressure. system with T-tape was established shortly after
To this end, we continued our testing sites in 5 different transplant. ‘Everleaf Emerald Tower,’ ‘Obsession,’ ‘Passion,’
locations in Maryland, each with different temperature ‘Devotion,’ ‘Thunderstruck,’ ‘Aroma,’ ‘Prospera,’ and ‘Red
and humidity levels. We selected sites in north central Opal’ basil were established at these two sites. Once the
Maryland (Carroll County), central Maryland (Howard), plants were 20-24,” we harvested the plants by cutting
southern Maryland (Charles County), and eastern them to about 4 inches above the soil line. Each time the
Maryland (Wicomico County), with each site having plants grew back to 20-24” tall, another harvest was taken
different light and air circulation. Warm, humid conditions and recorded. The foliage was examined, and symptoms
at a site greatly influence the disease pressure. This of downy mildew were noted at a 14-day interval.
will vary from site to site you are growing in. The site in Finksburg - At this site, six plants of each cultivar
Westminster was at the top of a field in an open, airy ‘Devotion,’ ‘Passion,’ ‘Thunderstruck,’ ‘Aroma,’ ‘Obsession,’
space. The sites in Howard at the Central Maryland and ‘Emerald Towers’ were planted in containers on a
Research and Education Center (CMREC) and Brookeville deck with full day sun.
were in areas with 10 hours of direct sunlight. Still, they
were surrounded by plant material that reduced air Charles County - The cultivars tested at this location were
circulation. The length of direct sunlight was reduced to ‘Devotion,’ ‘Passion,’ ‘Thunderstruck,’ ‘Aroma,’ ‘Obsession,’
8 hours by September. At the CMREC Upper Marlboro and ‘Emerald Towers.’ At this site, there were four reps
research farm, the plants were in full sunlight, with planted, with six plants in each plot. Plants were put in
westerly winds slightly blocked but otherwise good the ground on June 16, and dead plants were replaced
circulation since the site was close to the highest point on on June 21. The plots were fitted with 3’ black plastic in
the property. The site in Charles County was in full sun, as flat rows with 5’ between each row and a single line of
was the site in Wicomico County. drip tape. There was one harvest at this site. The harvest
included cutting plants down to about three inches above
For brevity, we will describe just a couple of the locations:
the soil line and weighing yields. At this location, leaves
Westminster and Brookeville sites - These sites were with DM symptoms were incubated to ensure downy
established on June 17, 2022. Each plot consisted of 10 mildew was the reason for the symptoms.
Varieties tested at the five sites:

BASIL YEAR INTRODUCED SOURCE
Prospera 2019 Israel

Devotion 2018 Rutger’s

Obsession 2018 Rutger’s
Thunderstruck 2020 Rutger’s

Amazel 2019 Proven Winners
Aroma (susceptible cultivar) Ocimum basilicum. Genovese aroma basil has strong
fusarium tolerance
Everleaf Emerald Tower 2021 Genovese basil that’s been bred to flower up to 8 weeks
later than standard varieties. Pan American Seed
Company
Red Opal Basil Ocimum Developed by John Scarch and Joseph Lent at the
basilicum University of Connecticut in the 1950s. In the previous
three years, we had not found downy mildew active on
this cultivar at the Brookeville site.

56 SPRING 2023 • Free State News