Citrus crop

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... 

Most potassium in fertilizers is the simple chloride salt, having a 60-62% K2O equivalent. Certain crops such as potatoes and tobacco do not like high amounts of chloride. For these crops KNO3, K2SO4, or K2Mg(S04)2 may be used. Florida citrus crops need magnesium nutrients so K2Mg(S04)2 is favored there. 

Petroleum oils are widely used in the treatment of citrus crops in California. They have proved to be the most efficient insecticide per unit of cost for most of the dominant pests of citrus in this area. In an effort to improve oil sprays from the standpoint of both tree safety and insecticidal effectiveness, the research on oil sprays at the University of California Citrus Experiment Station has been intensified. Part of this new effort has involved close cooperation with other laboratories, particularly with the New York State Agricultural Experiment Station at Geneva. The same petroleum fractions and other hydrocarbon compositions were tested simultaneously against citrus and deciduous fruit pests. This coordinated approach has been mutually advantageous, and it is expected that it will lead to an understanding of the fundamental principles involved in the use of hydrocarbon oils as insecticides in general. 

About two thirds of the citrus produced worldwide is consumed as fresh fruit. Unfortunately, citrus utilised as fresh fruit cannot constitute a source of commercial flavours. However, in certain high-production countries such as the USA (Florida) and Brazil, the majority of the citrus crop is processed. In Florida over 90% of the orange crop is processed and is a major source for citrus flavouring material. Citrus fruits are processed primarily into juice, but oil from the outer layer of the peel, flavedo, and the condensate from making concentrated juice are also major sources of flavour products from citrus fruit. 

Of the 1978-79 domestic citrus crop, some 6,855,000 metric tons of oranges from a total of 8,340,000 metric tons went to the production of processed products. Of the 2,490,000 metric tons of grapefruit that were harvested, 1,510,000 metric tons were utilized in processed products. A similar picture can be painted for the other domestic citrus crops. It is easy to see that the market for processed citrus fruit in the U.S. is ex-... 

Cover Crops Ideal cover crops should suppress weeds and provide little interference with the citrus crop. Jones and Embleton (1967) recommended using legumes in young citrus orchards before weeds become thoroughly established. However, in mature orchards, other alternatives such as mustard species are used as cover crops in citrus orchards. 

With the exception of 2,4-D and gibberellic acid treatments of a variety of citrus crops, where improved fruit set, reduced fruit drop, and the ability to delay harvesting without loss of fruit quality are recognized benefits, few applications have been developed for the use of hormone-type regulators in tropical fruits. Recent work has shown that gibberellic acid will delay postharvest ripenining and improve the quality of bananas and that napthaleneacetic acid treatment of oil palm to delay fruit abscission has increased both yield and oil content. 

We examine oranges, rather than all citrus crops, because oranges are the primary citrus crop produced in the San Joaquin Valley. We consider... 

Chemical Name 5-bromo-3-sec-butyl-6-methyluracil 5-bromo-6-methyl-3-(l-methylpropyl)-2,4-(l//,3//)pyrimidinedione Uses Herbicide applied to soil to control annual and perennial grasses, broadleaf weeds, and general vegetation on uncropped land also used for selective weed control in apple, asparagus, cane fruit, hops, and citrus crops. 

Chemical Name 0,G-dimethyl-S -[-4-oxo-l,2,3-benzotriazin-3(4//)-yl)methyl)] phosphorodithioate 0,0-dimethyl-5 -[3,4-dihydro-4-keto-l,2,3-benzotriazinyl-3-methyl) dithiophosphate Uses nonsystemic insecticide and acaricide for control of insects and pests in blueberry, grape, maize, vegetable, cotton, and citrus crops. 

Uses Bromacil is a colorless crystalline solid. It is used for the control of annual and perennial grasses, broadleaf weeds, and woody plants.1213 Bromacil is a herbicide used for bush weed control on non-cropland areas. It is especially useful against perennial grasses. It is also used for selective weed control in pineapple and citrus crops. It interferes with photosynthesis of plants. It is available in granular, liquid, water-soluble liquid, and wettable powder formulations. 

Unsubstituted uracils have no herbicidal activity but certain derivatives substituted in the 3,5,6-positions are active. The most important examples are bromouracil, terbacil, and lenacil. These compounds were introduced by DuPont in 1963. These herbicides are applied to the soil and are used for selective weed control. Bromacil and terbacil are pre- and postemergence herbicides they control a wide spectrum of grass and broadleaf weeds when applied early in the growing season. These compounds must be carried to the roots by soil moisture, where they are absorbed and translocated to the rest of the plant. This family of herbicides is used for asparagus, sugar cane, pineapple, apple, and citrus crops. 

Pesticide residues may contaminate citrus peel oils as well. Cultivation of citrus crops commonly involves the use of chemicals such as fertilizers and pesticides. Regulations are increasingly stricter in terms of residual levels of pesticides because of the application of citrus oils in food, pharmaceutical, and cosmetic industries (75). Citrus peel oils, extracted from citms peels, contain a higher concentration of pesticide residues than the fruits, due to the direct contact of the peels with pesticides. Organophosphorus and organochlorine pesticide residues in citrus peel oils have shown a steady decrease in recent years (76). 

Before spraying oil on citrus crops, check with local Cooperative Extension Service agents for the best timing of sprays for your area and cultivars. On lemons, oils are usually applied in April and May for other citrus crops, oils are used in late summer or fall. (Navel oranges are very susceptible to damage from oil,. so do not spray them after September 1.) Avoid treating citrus trees while mature fruit is present, because fruit may drop or the color and quality may suffer. 

How is the enthalpy of fusion of water involved in protedng citrus crops from freezing ... 

Spraying water in the citrus grove is effective if the temperature drops only a few degrees below the freezing point of water. Why can t this procedure be used to protect citrus crops in areas where the temperature drops far below freezing ... 

Alkane hydrocarbons are often used as fuels to provide heat and, sometimes, light. The smudge pots shown on the left produce heat that helps prevent cold-weather damage to citrus crops. The gas lantern gives off light, and the gas-log fireplace provides both heat and light. 

The primary use of chlorobenzilate is as an acaricide for mite control on citrus crops and in beehives. Historically, it was used as a synergist for DDT. Although classified as a Restricted Use Pesticide in... 

MAJOR USES Used in agriculture as an acaricide for spider mite control, acaricide for citrus crops, cotton, fruits and nuts used in hives against the bee mite synergist for DDT. 

Furthermore, the amount of potentially leaching nitrates was shown to be lower in organically managed soils than in conventional ones. Consequently, the introduction and the spread of the organic farming system in the citrus cropping area should reduce the risk of polluting the waters. 

Uses Nonsystemic insecticide and acaricide forconpol of insects pests in blueberry, grape, maize, vegetable, cotton and citrus crops. 

Limonin bitterness is especially acute in juice obtained from short maturation time fruits such as navel oranges. Juices obtained from most of the other citrus crops, such as Valencia oranges, usually do not have the limonin bitterness problem, as the concentration of limonin has decreased sufficiently by the time the processing season starts. Juices from navel oranges, particularly early- to mid-season fruits, can contain over 30 ppm of limonin, which is well above the bitterness detection threshold of 6 ppm. Grapefruit also has significant levels of limonin, which vary from 10 ppm in the early season to 1 ppm or less in the late season. 

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