Low-Light Pulses Improves Postharvest of Fresh Basil

Herbs are often incorporated in fresh flower bouquets, including a variety of uniquely scented basils. Fresh basil (Ocimum basilicum) has a storage life of 4 to 5 days at room temperature. As a plant of tropical origin, it is susceptible to chilling injury below 12C (about 53F). The postharvest life of fresh basil is limited by senescence of green leaves. Since it is known that the initial phase of senescence induced by darkness is reversible, this study assessed the feasibility of using low intensity light pulses to delay senescence of basil leaves.

Basil leaves were irradiated each day for 0, 30, 60, 90, 120 and 180 minutes with low intensity white light (30-37 µmolm-2s-1). Postharvest indicators evaluated included chlorophyll loss, protein degradation, ammonium accumulation, changes in sugars and leaf appearance.

The daily 2-hour treatment with low intensity white light pulses delayed senescence. Light effects were determined to be partly systemic, suggesting that even with a treatment where light does not uniformly reach the leaves, postharvest life will be improved. The use of light is considered an inexpensive, easy to apply technology for improving postharvest life.

Costa, L., Y.M. Montano, C. Carrion, N. Roiny, J.J. Guiamet, 2013. Application of low intensity light pulses to delay postharvest senescence of Ocimum basilicum leaves, Postharvest Biology and Technology, 181-191.

Ethanol Use on Tweedia caerulea

Tweedia caerulea is a native of Brazil and Uruguay with bright blue star-like florets. Senescence is first noted when the flower petals change from light blue to pink, after which the flower closes. It was previously reported that T. caerulea is sensitive to ethylene. This study investigates the effect of ethanol on vase life, ethylene production and sensitivity to ethylene of cut T. caerulea.

Newly-opened flowers were harvested in the morning and trials started the same day. Vase life was considered terminated when the petal angles became acute, indicating flower closure. If flowers did not close, the vase life was determined by apparent necrosis of the petals.

Continuous treatment with ethanol delayed senescence of T. caerulea flowers. Ethanol reduced sensitivity to ethylene, but stimulated autocatalytic ethylene production. This suggests the delay in flower senescence induced by ethanol was not attributable to reduced ethylene production, rather to a reduced sensitivity to ethylene. Interestingly, the ethanol treatment did not delay the change in petal color, the first indicator of flower senescence.

Pun, U.K., K. Ichimura, T. Niki, 2013. Ethanol reduces sensitivity to ethylene and delays petal senescence in cut Tweedia caerulea flowers, Plant Growth Regulation, 125-130.

Newly Developed Round-bale Unroller for Weed Control

Mulches used between rows serve to suppress weeds and add organic matter to the soil, among many other benefits. While hay and wheat straw are typical organic mulches, applied using square bales, an alternative may be using round bales of old or spoiled hay which is no longer good for livestock feed. There is an opportunity to significantly decrease the labor of mulch application by using a round bale unroller. However, some modifications must be made to the standard round bale unroller to apply the mulch between row-beds since the implement normally carries the bale on the centerline of the tractor. The modifications will allow the tractor to straddle the bed, unrolling the mulch in the aisle.

The modifications can be made to any conventional bale unroller as long as the clamping arms are open at the end where they pivot on the toolbar, allowing the additional length of the toolbar to be added. The toolbar was extended 27 inches, resulting in an offset of 36 inches from the center of the row. The modifications assume using 4-foot wide round bales, noting larger bales may be too heavy for safe handling.

Another important modification was the addition of a hydraulic top link. This allows for rolling bales out to a smaller diameter without lowering the tool bar to a height that could damage plants or the bed structure.

While costs will vary dependent largely on metal fabrication, the bale unroller in this project was purchased for $1,300, the hydraulic top link was added for $300 and the offset toolbar modification was an additional $470.Other considerations include the need for a minimum 35-hoursepower tractor with either a Category I or II three-point hitch system. In addition to the tractor driver, an additional worker is usually needed to walk behind the bale to assist in peeling off the layers of mulch. While the coverage area can vary considerably, this trial applied a single layer, covering a distance of 250 to 300 feet with per round bale. This trail saw effective weed control at an application rate of 15,000 to 20,000 lbs/acre.

For detailed modification plans, visit this University of Kentucky website: http://www.bae.uky.edu/ext/Specialty_Crops/plans.htm.

Wilhoit, J., and T. Coolong, 2013. Mulching with Large Round Bales between Plastic-covered Beds Using a Newly Developed Offset Round-bale Unroller for Weed Control, HortTechnology, 511-516.

Megan Bame

Megan Bame is a freelance writer in Salisbury, North Carolina. Contact her at [email protected]