PLANT STRESS BIO-PROTECTANT
ECTOL ON CHERRIES TO REDUCE
STEM BROWNING AND CRACKING
Since 2005 Australian growers have been applying Ectol to Cherries,
to assist with frost resistance, plant health and heat stress.
Field experience suggests that Ectol is helping with the maintenance of stem greening, stem detachment
and the reduction of skin cracking, all of which are serious economic problems for growers.
Stem browning and pitting occurs during storage and is a consequence of the high respiration rate
of cherries continuing after harvest and the extent varies by storage conditions and variety.
Additionally cherries have a thin waxy cuticle which has a limited capacity to restrict water loss from
the fruit surface and the stem.
Cherry cracking is a more complicated and uncertain phenomenon and researcher hold varying views as to the
causes. What is understood, there is a malfunction of the waxy cuticle or outer layer and the epidermal cells below.
Susceptibility to cracking varies by variety, season and management practices, but microscopic fractures of the
cuticle may predispose the fruit to cracking. The cause of the fracturing may possibly be due to variable water
supply to the roots.
The prevailing theory for cracking is that surface water penetrates the fruit through the factures, increasing the
volume of the fruit and initiating cracking. The driving force is the osmotic potential between the surface water
and the fruit.
Further studies show that the uptake of water from the roots increases the turgor pressure within the cherry
causing the weakened surface to crack.
Management strategies to reduce cracking:
1.0 Irrigation management: Assuming that fractures predispose the cherry to cracking and that moisture
variability may be involved, close attention must be given to the maintenance of consistent soil moisture as
the cherry ripens.
2.0 Crop protection: Whilst covers reduce the surface water on the skin entering the fruit, they do not limit
soil saturation which is also shown to lead to cracking.
3.0 Calcium Sprays: The plant response in terms of cracking has been inconsistent but calcium spays
provide a low cost option and should be considered.
Calcium forms calcium pectate in the middle lamella of plant cell walls, cross bonding proteins, reducing their
solubility, providing strength to the cell wall and without which plants develop “leaky cells.” However what is
uncertain is the contribution calcium sprays make to maturing cherries and the timing of sprays needs to be
considered.
Calcium is absorbed through the cuticle and remains on it, reducing the electro-chemical potential of
rainwater on the surface, thereby reducing the osmotic water uptake by the plant. Calcium may also
reduce the cuticles permeability to water.
4.0 Plant Growth Promotants: Trials using auxins and gibberellins in combination with calcium
sprays have been shown to reduce the incidence of cracking.
Farmers Marketing Network Pty Ltd. A.C.N: 18 001 629 992
Address: PO Box 525 Drummoyne NSW 2047, Australia Tel: 02 8753 1304 Fax: 02 8753 1419 Mob: 0438 918135
Email: [email protected]
Ectol a plant stress protectant:
The natural extracts in Ectol, including amino acids, osmoprotectants, plant growth
promotants, sugars and minerals help plants resist stress and whilst field experience and trials
have demonstrated the value of Ectol in stress mitigation and recovery, its role in the
reduction of cherry splitting, stem browning and polling is unqualified.
Ectol has biochemicals that protect the cell membrane and increase the hydration of cells when
under stress. Also there are materials that relate to the formation of lignin monomers and phenolic compounds
involved with cell wall strength.
The expectation is therefore that Ectol should be able to maintain the hydration and “greenness” of stems and
strengthen the cuticle/epidermal layer, thereby reducing the fracturing which sets up the potential for cracking
in very wet conditions.
Growers have reported a reduction in these physiological events by applying Ectol later in the growing season
and formal trials are being undertaken.
Calcium + boron Chelate:
Whilst all soluble forms of calcium have been shown to be beneficial to fruit quality, chelated calcium is more
effectively absorbed through the leaves and fruit and made available within the cells.
Growers may consider therefore maintaining a calcium spray programme throughout the growing season and
certainly applying Calcium+boron Chelate with Ectol as the fruit matures.
Suggested Summer Foliar Programme for Ectol and Calcium + boron Chelate.
Weeks before
harvest
Weeks before
harvest
Weeks before
harvest
5
3
1
Ectol
5 L/ha
5L/ha
5 L/ha
Calcium +boron
5L/ha
5L/ha
5L/ha
Ectol and Calcium + boron chelate can be applied with conventional crop protection spays by addition to the
made up tank. A jar test is recommended.
J H McKay (2009)
Refs: Christensen 1996, Jedlon and Schroder 2005, Wermund 2005, Seke L 2008
(Note: these comments and recommendations reflect the opinion of the writer and the grower should seek his own advice if necessary.)
PLANT STRESS BIO-PROTECTANT
Farmers Marketing Network Pty Ltd. A.C.N: 18 001 629 992
Address: PO Box 525 Drummoyne NSW 2047, Australia Tel: 02 8753 1304 Fax: 02 8753 1419 Mob: 0438 918135
Email: [email protected]