Frost fruit

The least hardy fruit producers showed marked reductions in fruit production and significant leaf losses. In addition up to 20% of the trees were killed outright by the frost. The susceptible populations were either killed outright (up to 82%) or failed to produce any fruit crops and were generally defoliated. 

The warm-weather climates necessary for citrus orchards generally minimize the risk of frost conditions. Nevertheless, occasionally measures are needed to protect the trees and their fruit from freezing temperatures. Citrus crops become threatened when temperatures fall below 28°F for four hours or moreJ l Heating... 

To achieve a good intrinsic visible fruit quality, biotic and abiotic stress to the trees has to be controlled. Therefore, conventional fruit orchards are often fitted with relatively expensive installations such as wind break hedges, hail nets, irrigation systems and wind machines for frost prevention, irrigation and liquid fertilisation facilities and wild animal fences. Apart from liquid fertilisation systems, most of these installations can also be installed in organic orchards and help to assure yield and quality security. 

Late cultivars will not ripen until they have been in store for a while. The refrigerator is ideal for storing apples, but a frost-free shed, basement, or attic is adequate and more economical. Aim for cool, dark, slightly damp conditions. Only store perfect fruits. 

Symptoms Overnight, flowers and buds become discolored, usually brown. Frosted blooms may not produce fruit. Leaves and stems turn brown or black young growth toward the outside of the plant will be most affected. Apple skins may be russeted, usually at the flowering end of the fruit opposite the stalk. Damage may not be noticed until the fruit has developed. 

The addition of heat to ahody of water, a condition known as thermal pollution, represents virtually no problem for humans. In fact, thermal pollution can even have certain advantages. For example, water heated by such processes can he used to spray on fruit trees to prevent damage from frost. It can also he used, under controlled circumstances, in aquaculture, the controlled cultivation of fish and seafood. 

The thin small blades of a Microplane zester cut spices, such as whole nutmeg, and the peel of fruit into minuscule pieces that are perfect for incorporating into batters and frostings. The zester slices into just the top outermost layer of citrus, so the bitter white pith does not get zested. The tool is really sharp, so be especially careful with kids around. This is definitely an essential for your baking kitchen you will find Microplanes in kitchenware stores. 

All crop production, except protected cropping (for example, glasshouse, plastic covered), is vulnerable to the weather. Measures to combat frost and drought are common to most kinds of crop production wind protection (by shelter belts and so on) is practised for only a few crops (e.g. top fruit). In general, apart from choice of location, little can be done about solar radiation, rainfall or temperature. Problems with weeds, pests and diseases are also common to all crops but the remedies available to organic producers are much more limited than for conventional farmers. 

Table 2.3. Sensitivity of different species of fruit to winter frost.

Sheltered locations are the best type of location for fruit growing. They are protected on the north-east side (by woods, buildings, etc.) and are open towards the south-west. This provides the possibility of air flow in the latter direction and reduces the risk of frost. 

Only relatively flat sites are suitable for nurseries. On sloping sites there is a risk of erosion because the soil has to be kept bare. In addition, locations where there is a risk of frost (winter frost and late frost) should not be used as nurseries, especially for the propagation of stone fruit and pears on quince rootstocks. Nurseries should preferably be set up on medium-heavy soils. Humus-rich, loamy sand soils or sandy loam soils are especially favourable. A soil index well above 50 is advisable for nurseries. 

P22 Poland M9 X Antonovka < M9 Very frost-hardy, high production capacity, good fruit quality (colour development) Root at severe risk of drying out (tree failures), juvenile and adult forms... 

B9 (Budagovsky) Russia (M8 X Red Standard] > M9 Frost-hardy, better colour development, resistant to collar rot Less productive than M9, susceptible to fireblight and woolly aphid. Smaller fruit Rapid spring development... 

For optimum fruit quality, almost all pear varieties need a warm site, rather similar to that required for wine grapes. If these conditions are not present, the fruit very often does not have the desired melting texture and has little flavour in extreme cases the fruit may taste carroty . This applies particularly to late-ripening cultivars. Pear trees are somewhat more sensitive to winter frost than apple trees, and are at severe risk from late frosts because flowering is about 10 days earlier. 

Since plums and sweet cherries generally flower earlier than apples, a frost-free location which is sheltered from the wind is preferable. Antifrost irrigation is not possible for stone fruit. The soil should be well-drained. Plums tolerate a somewhat heavier soil than cherries. The choice of rootstock can compensate for these disadvantages, however. 

Curbs growth, frost-hardy, not always compatible, medium to high soil requirements, good fruit size can be obtained by pruning and additional irrigation. Not suitable for replanting after P. avium or after itself. 

Airy sites in full sun, but protected from strong winds and late frosts, are the most suitable sites for all species of small fruit. 

Meeker medium ripening time, medium-sized, aromatic fruits that are easy to transport. Highly vigorous cultivar with increased frost tenderness. Not very susceptible to root rot. 

A layer of straw is placed beneath the strawberry plants to make sure that the fruits stay clean and to prevent the spread of grey rot and rhizome rot [Phytophthora cactorum). In addition the straw conserves soil moisture (this can also be a disadvantage), suppresses weeds and makes it easier to move around. The straw (80-100 kg/acre) is put down just before the fruits touch the soil. If this job is carried out before or during flowering, there is an increased risk of damage from late frost (because the soil is... 

PRIMARY INFECTIONS. The mildew fungus overwinters as mycelium in the buds. If there is very severe frost in winter, some of the infected buds may die off, as the bud scales are not completely closed. In the closed buds the mycelium produces conidia, which infect the young leaves, blossoms and fruit when the buds open. Infection may occur at the greenbud or redbud stage if weather conditions are favourable. The first symptoms of primary infections can then be seen on the leaves and petals at flowering. Apart from the climatic conditions, for mildew infection to develop the tree must also have susceptible tissue (very young leaves) available. The leaves acquire age resistance to mildew at an even earlier stage than they do to scab. 

PREVENTIVE. If possible, remove fruited canes in the same year (Caution this increases the risk of frost damage). 

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