New Young Tree Shipping Sleeves.   Corrugated cardboard paper sheets held with rubber bands were developed into shipping sleeves for citrus nursery trees produced in reusable rigid containers. The sleeves allow for shipping of the plants without the containers, avoiding their unnecessary handling in the field and return after planting of the trees. Their cost is approximately US $ 0.04 a piece. The trees ready for shipping are removed from their original container and placed into the cardboard tubes previously mounted with the aid of a rubber band. The shipping sleeves last for at least 30 days with regular irrigation. In addition, the sleeves can be used as tree wraps after planting, reducing trunk sprouting and damage by leaf-cutting ants, and facilitating herbicide application.  The use of rigid containers instead of plastic bags in the production of citrus nursery trees eliminates the need for pruning of the root system before planting. The containers have internal ridges and open bottom which prevent root curling and tap root bending. Trees produced in plastic bags on the other hand require careful pruning of curled tap roots as well as  pioneer lateral roots in a cumbersome operation before planting, with increased risks of disease infection. 

Vine Orange. Branches of this unique orange variety lack self support and, therefore, must be sustained by structures like trellises or espaliers. The vine orange was introduced into the germ plasm collection of the Centro de Citricultura Sylvio Moreira  more than 30 years ago and is now grown by gardeners and horticulturists as  dooryard arrangements. The fruit is a true orange, maturing midseason, with agreeable flavor as a fresh fruit as well as juice.  

The Importance of Disinfestation.  Pediluvio is the name citrus nurserymen in Brasil gave to the germicide box placed at the entrance of their production areas for shoe disinfestation. Its importance was confirmed by tests with shoes contaminated with Phytophthora, the fungus associated with foot and root rot in citrus. Detection of the fungus in the soil attached to the shoes was reduced from 50% before stepping on the pediluvio to none afterwards. On external areas the pediluvio must have a top for protection against rain or irrigation water. Tested germicide powder consisted of equal parts of copper sulfate and hydrated lime.

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Tree Architecture & CVC. Tree damage by the CVC (Citrus Variegated Chlorosis) bacteria is mostly due to clogging of the vessels that transport water and nutrients from the soil to the canopy. This transport goes necessarily through the trunk of the tree. It is possible that ideal water/nutrient flow can be obtained by conditioning trunks to have large diameters and short lengths, and by keeping their vessels unobstructed. This can be obtained in the nursery by pruning the single orange-scion stem coming off the bud grafted on the rootstock to a short 5 to 10 cm (2 to 4 inch)  height. As the tree grows, most of the tissues in the  trunk will be from the rootstock, which is generally resistant to colonization by the CVC bacteria, thus preventing clogging. Typical orange trees have trunks constituted mostly by orange tissue, highly susceptible to the bacteria. In addition, low topping induces short and thick trunks, with a greater number of vessels. The bacteria move easily up and down the vessel they colonize, but have great difficulty in moving across the trunk, from vessel to vessel. The larger the number of vessels in the trunk the longer it will take for the latter  to become clogged.  Increasing the number of scaffold branches also seems to result in a larger trunk. Therefore, the connection between the root system and the tree canopy could be maximized through large and short trunks with free-flowing vessels. It remains to be seen in practice whether this will result in a commercially healthier, more CVC-tolerant orange tree. For this purpose we supply our interested clients with small number of trees  with the experimental architecture for field evaluation . Other citrus diseases like Blight, Foot Rot, and virtually all systemic disorders are also serious because they affect the trunk. Therefore, additional benefits could arise from  short, thick and unobstructed root-to-canopy interfaces.

Biodegradable Wrap. A significant development in citrus nursery-tree production. The trees can be planted   with the wrap, which is rapidly destroyed by natural soil agents. Tree handling and planting are facilitated and less expensive since the ball of soil around the roots remains undisturbed. In addition, water drainage during storage and handling is perfect, preventing root diseases. Non-degradable wraps must be removed, resulting in higher costs and losses due to root-ball disruption. Special stalks obtained from grasses growing near water bodies were initially common as wraps. However, those areas are now under mandatory preservation. The best wraps today are made using burlap tied with sisal cord, both commercially produced. Similar wraps are successfully utilized in citrus nursery-tree production in California, US.


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Nursery-Tree Decks. The idea occurred to us in 1990. Our objectives were to store nursery trees after digging-out until customer pick-up. Decks were built using solely concrete poles initially, and later introducing wooden pallets, guaranteeing a floor height of 20 to 30 cm (8 to 12 inches).  This prevented excess water usually accumulated at soil level, providing an ideal environment for healing of the root system trimmed at uprooting. Disease prevention is thereby highly favored. Within 2 to 4 weeks the dug-out trees are fully recovered and well established in the root balls. New fibrous roots start to develop in the process. As a result, transplant stress is significantly reduced, and costs minimized due to higher survival rates, lower maintenance requirements and excellent root disease prevention. Our decks are typically 4.5 x 4,5 m (15 x 15 ft) in dimensions, countering ca. 1500 trees. They cost between US$ 350 each when only concrete poles are used and  US$ 85 when wooden pallets replace some of the poles. The more expensive structures, however, last significantly longer.

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Black Concrete Floors. Our experiments on floor characteristics for potted citrus screenhouses have show 2 interesting results: 1. concrete floors are the only type which allows for adequate sanitation and easy prevention of fungi and bacteria harmful to citrus plants. Ground sterilization can be achieved by washing or spraying with adequate chemicals. In addition, concrete floors provide the shortest survival time for citrus pathogens, in case of ground contamination; 2. black is the ideal ground color for avoiding high temperatures in the screenhouses. This last conclusion doesn't seem evident at first but the dark ground seems to absorb all radiation which penetrates the plastic cover, avoiding its entrapment in the house ambient as in the greenhouse effect. Warming up of the ambient air through heat diffusion from the ground, on the other hand, is much slower and can be easily controlled with irrigation if necessary.

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Woodless Buds.  Our company developed a new type of citrus budding in order to insure for our plants freedom from the bacteria that cause the disease Amarelinho or Citrus Variegated Chlorosis (CVC). These bacteria live in the plant but are restricted to the wood, and if this tissue is totally removed from citrus buds before propagation,  the safety of the whole process is warranted. A method for obtaining woodless buds has been used in our citrus nurseries since 1993. Only the bark containing the bud-eye which will sprout and regenerate a new plant is removed from the budwood sticks. Care must be taken to eliminate wood tissue present in the leaf petiole and thorns adjacent to the buds. In addition, it is important that the buds be totally dormant,   to insure that the connection process between the wood tissue and the new buds has not been started. It is a highly technical procedure, yet very simple. Woodless buds are mainly utilized  in the establishment of screened budwood increase blocks, from which buds are then taken for  nursery propagation. The material in the budwood increase blocks has been selected among the best plants in commercial groves in the last 25 years, and freedom from CVC is triply guaranteed by : 1. budwood heat treatment, 2. utilization of woodless buds, and 3. constant indexation.


New Rangpur Lime. A new Rangpur lime clone called 'Citrolima' is being studied by our company since 1991.  It originated in a Rangpur lime seedbed as a mutation or a natural hybrid. The plants are more vigorous, with larger leaves, and have less lateral sprouting than the regular Rangpur lime. In addition, they are completely resistant to Scab. Their development in the nursery, therefore, is highly satisfactory.  Foot Rot resistance has been tested similar to that of the regular Rangpur lime. All other characteristics seem to be similar to those of the common Rangpur. In the pictures shown here where there are 2 plants, the one on the left is of regular Rangpur lime and the one on the right is of the 'Citrolima' Rangpur, both with the same age from sowing. The third picture shows a bed of 'Citrolima' plants 90 days after transplanting. The new clone produces  abundant crops of fruits with 20 seeds each in the average. The seeds have a degree of poliembriony higher than those from the common Rangpur. Six-year-old Valencia trees on 'Citrolima' Rangpur  are showing excellent field performance.

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Mother Trees. We have finished harvesting our mother-trees 1999 crop. The trees are in commercial groves originated from superior trees of at least 20 years of age selected in the last 25 years. One hundred to 150 candidate trees were selected in these orchards and their productivity recorded every year. Average yields over the last 3 or 4 harvests of the best 10 plants of the main orange varieties in Brazil are shown in the following table. All phytosanitary and horticultural aspects were also considered in the selection process. Propagation material is then collected from the best plants, tested for systemic diseases, heat treated, and budded using woodless buds inside screened budwood houses. Groves originated from nurseries propagated with material from these budwood houses have shown improved field performance, indicating that mass selection at each generation also works for clonally propagated citrus.


Variety, age
(Crop Years)
Boxes/tree Boxes/ha Boxes/A Metric Ton/ha Short Ton/A
Natal, 11 years
(Years 8 to 11)
6,23 2075 840 84,6 37.7
Valencia, 7 years
(Years 5 to 7)
5,57 1855 750 75,7 33.8
Pera, 11 years
(Years 8 to 11)
4,82 1605 650 65,5 29.2