Fruit setting

Pollen grains of another species, parthenium (Parthenium hysterophorus L.), contained growth inhibitors which inhibited fruit set in many test species (Sukhada and Jayachandra 1980). However this plant is a noxious weed and its pollen is strong, therefore use of parthenium in agriculture is unlikely. 

In general, the control of insect pests of cacao has been neglected. Also, little is known regarding the effect of insecticides on cacao. Cardona (9) in Colombia has studied the influence of some insecticides on the pollination and fruit setting. He used various preparations of BHC Agrocide, chlordan, DDT, dieldrin, dieldrex, methoxychlor [l,l,l-trichloro-2,2-bis(p-methoxyphenyl) ethane], and toxaphene. 

Chemical weed control in cacao plantations with volatile weed killers is generally considered detrimental to pollinating insects and to the flower and fruit set. Recently Naundorf (28) and Oliver (33) in Colombia conducted tests with compounds derived from 2,4-D and with an ammonium salt of dinitro-o-cresol to determine the effect of these materials on the flowers. They found that dinitro-o-cresol can be used at the dosages commercially recommended, and that only the volatile 2-4-D derivatives at concentrations of 500 to 750 grams per plaza (6400 square meters) can be used. 

Many eaterpillars (here of a sawfly), adult beetles and their grubs, and of eourse slugs and snails, graze on leaves and sometimes stems. Other larvae mine or tunnel leaves. Leaf damage reduees the area where photosynthesis operates, sapping the plant s strength and redueing fruit set. 

Avoid the use of tobacco if you grow tomatoes, peppers or Irish potatoes. Tobacco coutaius tobacco mosaic viras (TMV) which will get ou your hands and be spread to plants which you touch. Equipment, insects or anything touching an infested plant and then another plant is also likely to transfer the disease from plant to plant. TMV is very hard to control and reduces both fruit set and fmit size. Total yield of TMV-infested plants may be reduced slightly or nearly wiped out. Leaves of infested plants may be distorted and will probably have a mottled appearance rather than a solid green color. Remove isolated plants showing these symptoms as soon as they appear. 

The most commercially successful PGRs are those that operate either through the inhibition of gibberellin biosynthesis, from mevalonic acid (Knee, 1982) or through the production of ethylene. These represent the two most valuable pathways for growth modification since they have key roles in extension growth, ripening, fruit set and dominance. 

Naphthyl)acetamide Compounds used in fruit setting... 

After fruit set, and through the stages of cell division and cell expansion leading to maturation, there is a constant decrease in the rate of... 

Blueberry better fruit set Celery extends winter crop Cherry (sour) combats cherry yellow virus... 

The results show that the role of gibberellin in fruit set and development must be thoroughly investigated. It has long been the viewpoint that auxins produced in the seeds control fruit set and development. 

The thinning of fruit on various specied of fruit trees and grapes is necessary commercially. Because this is difficult and costly to do by hand, however, growers have turned to the use of chemicals. Chemicals have been used to thin fruit set in apples, for example, since the early 1930 s. In addition to permitting crops to be produced annually be eliminating or reducing alternate-year bearing, this practice also enhances the size, color and quality of the fruit. 

Gibberellins are used in grapes for several different purposes. The present commercial practice in California is to spray twice, once at bloom for a loosening arid sizing effect and again at fruit-set stage for an additional sizing effect. 

Alar promotes fruit setting of grapes and accelerates by several days the maturing of cherries. It also is used on apples, prunes, tomatoes, peanuts, and various ornamental crops. On apple trees, Alar increases the firmness of the fruit and prevents it from dropping permaturely. On tomato transplants, the compound retards stem elongation. 

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. 

Several materials have commercial use as abscission agents (6). In cotton, the products Accelerate (endothall), Folex (merphos) and DEF (oxidized form of merphos) have been identified as defoliants. Amid-thin continues to be used to thin fruit set. 3-CPA and Peach-thin 322, formerly used as peach thinners, serve as reminders of the disadvantages of highly specialized markets. RELEASE and PIK-OFF are under development as citrus abscission agents. 

The pheromones can also be used to enhance a beneficial activity of the beetles. Nitidulids are primary pollinators of custard apple (Annona) flowers, but poor pollination has often been a problem (Gazit et al., 1982 Nagel et al., 1989). A new concept was to place pheromone lures in Annona trees to increase beetle density and enhance pollination, and Pena et al. (1999) found that pollination and fruit set were significantly improved when the pheromones were employed. 

Pena, J.E., Castineiras, A., Bartelt, R. and Duncan, R. (1999). Effect of pheromone bait stations for sap beetles (Coleoptera Nitidulidae) on Annona spp. fruit set. Fla. Entomol., 82,475 180. 

Promotion of fruit-set in apple by suppressing shoot growth with daminozide 2500 ppm applied at petal-fall stage. 

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