Journal for 6th August 2010
Last week we looked at Quality thinning of Apples - this week we concentrate on Pears
In the Journal for 25th June I touched on Pear thinning; with Conference Pears expected to be ready for harvest in September, now is the time to complete any quality thinning and if possible irrigate to maximise fruit size.
Thinning: The prime targets for pear thinning are; pears which will not achieve a marketable size, fruit with poor shape and skin finish.
Size; the optimum value for pears depends on fruit size above 60mm at harvest which falls into the loose pack range. Pears are marketable in polybags from 50mm - 63mm, but the market can only absorb 25% in the polybag range. The customer preference for larger pears dictates 75% in the loose format.
By using the projected size curve we can identify fruit which will not achieve 60mm.
Any Conference Pears below 45mm now, are unlikely to reach 60mm at harvest, so it is possible to thin now to achieve the right balance of fruit size.
Shape; using a guide from our marketing agency we can identify fruit which will be rejected during the packing operation.
Skin finish; EU and customer specifications allow very small amounts of rough russet; smooth russet is generally allowed up to circa 60% of the surface area.
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By removing fruit exhibiting defects clearly below the guidelines we will improve dramatically the value of our harvested fruit.
Irrigation;
By applying water in the weeks leading up to harvest, Conference size can be improved considerably. We must not start applying water before vegetative growth has stopped; we can determine this by the terminal buds forming; this would upset the fruit bud formation for next season.
In conversation yesterday with an old friend, Mark Holden of Adrian Scripps Ltd. the largest UK grower of Pears, Mark said the water applied right up to harvest will transfer straight into improved pear size, in fact, he said it is almost impossible to apply too much water in that period.
20 years ago this water would have been applied with an overhead sprinkler system delivering one inch a week; e.g. 22,000 gallons per acre, spread weekly over the whole orchard area; a lot of water!
Today modern and reliable trickle irrigation systems allow edequate water into a strip, no more than 2ft wide, which reduces the use of water dramatically. To put this into full context, if tree rows are 12 ft apart and irrigated area under the tree strip is 3ft wide, only 25% of the previous 22,000 gallons is used; e.g. 5,500 gallons per acre each week. The benefit in water conservation and of course cost saving is massive.Next week we will look at the benefit of summer pruning apple trees!
Take care
The English Apple Man
