Microbials play a variety of roles in crop production.
Why should microbial controls be a part of an Integrated Pest Management (IPM) program? The first, and main one, is that research shows that they work. Many microbial products in the market today are backed by trial data that shows when used correctly, microbials can be a very effective way to improve plant health, suppress pest pressure, and improve yields.
As with the N and K supply experiments, rootstock genotype was the major source of variation in shoot dry matter production under varying Si supply treatments, and volkameriana seedlings were more vigorous than seedlings of the other three rootstock genotypes (Table 10). Overall, plants grown with 2 mM Si in the nutrient solution produced approximately one third less shoot dry matter compared to seedlings grown without added Si.
As with the K and Si supply experiments, the major source of variation in shoot dry matter production under different pH treatments was rootstock (Table 14), and volkameriana seedlings were more vigorous than seedlings of the other three rootstock genotypes. The nutrient solution pH had no effect on dry matter production by any of the rootstock seedlings or on %N in shoot dry matter at harvest (Table 15).
Conventional agriculture is based on a high level of chemical inputs such as pesticides and fertilisers, leading to serious environmental impacts, health risks and loss of biodiversity. Pesticide reduction is a priority for intensive agricultural systems such as orchards. Reintroducing biodiversity in single crop systems can enhance biological regulations, and contribute to reduce the use of chemicals and to provide additional services such as run-off and erosion control. In tropical wet areas, weed control is difficult to manage without herbicides especially when orchards are not located in easily mechanised areas and when labour force is costly. Cover plants can be easily introduced in orchards and could be efficient in weed control and other functions. Based on this assumption, we developed a specific approach for the choice of adapted cover plants in single crop orchards to control weeds and provide additional ecological services. The approach was undertaken on citrus orchards in the French West Indies.
Ujwala Ranade-Malvi
Institute for Micronutrient Technology, India
Potassium is an essential element for plant growth and is an extremely dynamic ion in plant and soil system. As an ion, potassium is highly mobile in the plant system but only moderately mobile in the soil system. Just like humans require a balanced diet with appropriate amounts of carbohydrates, proteins, vitamins, minerals, fats and water, plants too require conditions of balanced nutrition. There is a pre-determined ratio of nutrients that is required by the plant system, depending on its life cycle, environment and its genotypic characteristics, to realize its maximum genetic potential.
Hiu-Ling Liao, Huiqin Chen & Kuang-Ren Chung
University of Florida, IFAS Citrus Research and Education Center
Postbloom fruit drop (PFD) of citrus is caused by the fungus Colletotrichum acutatum. The fungus infects flower petals causing brownish lesions that result in young fruit drop, leaf distortion, and formation of persistent calyces (commonly called ‘buttons’) after the fruitlet drops. Previous studies suggested that an imbalance of plant growth regulators such as auxin, ethylene, and jasmonic acid in C. acutatum-infected flowers, may contribute to young fruit drop.
F. Rivas, M. Juan, V.Almela, M. Agusti
Departamento de Producción Vegetal, Cátedra de Citricultura, Universidad Politécnica de Valencia.
E. Alos
Departamento de Citricultura, Instituto Valenciano de Investigaciones Agrarias. Valencia, Spain
Y. Erner
Department of Fruit Tree Sciences. Israel
The effects of girdling performed at various dates were evaluated during two consecutive years in high- and lowbearing commercial orchards of ‘Fortune’ mandarin and ‘Clausellina’ Satsuma mandarin. The time-dependent response was evaluated through fruitlet abscission, final fruit-set and yield as related to carbohydrate contents in developing fruitlets. A few days after treatment, girdling increased the soluble sugars content (SSC) in fruitlets, reduced the daily fruit drop, and thereby diminished abscission. Application of girdling to low-bearing ‘Fortune’ mandarin orchards was most effective 15 d before anthesis (DBA) and 35 d after anthesis (DAA). It increased yield by 125%. In high-bearing orchards, the best results were achieved by girdling 35 DAA, which increased yield by 28%.
Jose Linares, Johannes Scholberg, and Kenneth Boote
University of Florida, Agronomy Department
Carlene A. Chase and James J. Ferguson
University of Florida, Horticultural Sciences Department
Robert McSorley
University of Florida, Entomology and Nematology Department
Citrus is one of the most important crops in Florida. During the past decade, increased international competition and urban development, diseases, and more stringent environmental regulations have greatly affected the citrus industry. Citrus growers transitioning to organic production may benefit from premium prices, but they also face many challenges, including development of effective weed management strategies. Cover crops (CC) may constitute an environmentally sound alternative for improved weed management in organic systems.