California Agriculture
California Agriculture
California Agriculture
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California Agriculture, Vol. 29, No.3

Cover:  Almond branch showing severe failure of leaf buds; flower buds have bloomed and set fruit.
March 1975
Volume 29, Number 3

Research articles

Anystid mite: Citrus thrips predator
by A. R. Mostafa, Paul DeBach, T. W. Fisher
| Full text HTML  | PDF  
An anystid mite, Anystis agilis (Banks) (Acarine: Anystidae) has been observed feeding on larval and adult citrus thrips, Scirtothrips citri (Moulton) in orange groves in River-side and Ventura counties. The mite has also been known to prey upon aphids and citrus red mites. This observation is important because citrus thrips is one of the two or three most important citrus pests in California, yet very little is known about its natural control. Since the population density of the citrus thrips varies widely from year to year and between different groves in the same year, natural factors not yet understood are operating to produce these observed fluctuations. Thus, this new ob-servation of A. agilis as a predator of citrus thrips is of considerable interest.
Nitrogen uptake in midwinter lettuce
by Keith S. Mayberry, Roy S. Rauschkolb
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: In the imperial valley it has been a common practice for growers to apply high rates of nitrogen in the form of calcium nitrate, in an attempt to increase the growth rate of head lettuce during cold weather and to improve external head color.
Abstract Not Available – First paragraph follows: In the imperial valley it has been a common practice for growers to apply high rates of nitrogen in the form of calcium nitrate, in an attempt to increase the growth rate of head lettuce during cold weather and to improve external head color.
Climate effects on grapefruit and lemons
by E. M. Nauer, J. H. Goodale, L. L. Summers, Walter Reuther
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: Two previous articles in California Agriculture (November 1972 and April 1974) have repofled some climate effects on oranges and mandarins. This third and final report covers data obtained on Frost Marsh nucellar and Redblush nucellar grapefruit harvested over a period of five crop seasons beginning with 1967-68. Eureka and Lisbon lemons were harvested over four seasons beginning with 1968-69.
Abstract Not Available – First paragraph follows: Two previous articles in California Agriculture (November 1972 and April 1974) have repofled some climate effects on oranges and mandarins. This third and final report covers data obtained on Frost Marsh nucellar and Redblush nucellar grapefruit harvested over a period of five crop seasons beginning with 1967-68. Eureka and Lisbon lemons were harvested over four seasons beginning with 1968-69.
Bud failure in almonds: Variability of bud failure in Nonpareil almonds
by D. E. Kester, Rachid Hellali, R. N. Asay
| Full text HTML  | PDF  
Noninfectious bud failure (BF) affects certain almond varieties and has become increasingly widespread in recent years.Symptoms are produced by failure of vegetative buds (particularly on middle and terminal portions of shoots) to grow in the spring. This is followed by vigorous wide-angled growth from surviving buds. In some trees, particularly when other symptoms are severe, bands of roughened bark appear on some branches. As this pattern of bud failure develops, BF trees develop wild, disoriented growth patterns and hence the disorder is frequently called “crazytop.”Early work on the BF problem developed the concept of increased BF incidence with successive vegetatively propagated generations. At that time BF was attributed to a ienetic disorder with unstable characteristics. Since then, observations suggest that mvironmental conditions affect the stability m d expression of BF. Vegetative propagations done on the premise that plants propagated from a common parent remain the same, but this premise is not fulfilled in the 3F disorder. In other cases where variations lave occurred after vegetative propagation, the problem has most often been attributable :o environmental influences, virus infections or mutations. However, variability of noninfectious BF cannot, at present, be directly accounted for by any one of these factors. This series of articles adds further information on he nature of BF and discusses selection for reedom from BF within the Nonpareil variety. It documents the impact of environment on BF potential and expression and provides lata on yield reduction due to BF. Finally, it iutlines a system of management decisions or orchardists faced with almond trees afected with BF.
Selection for freedom from bud failure
by D. E. Kester, R. N. Asay
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: Principle control measures for BF include standardization of nursery stock for low BF potential in susceptible varieties like Nonpareil or selection of varieties with no BF potential. Avoidance of susceptible varieties in localities with prolonged high summer temperature may be required, as better information on relative susceptibility is obtained.
Abstract Not Available – First paragraph follows: Principle control measures for BF include standardization of nursery stock for low BF potential in susceptible varieties like Nonpareil or selection of varieties with no BF potential. Avoidance of susceptible varieties in localities with prolonged high summer temperature may be required, as better information on relative susceptibility is obtained.
Almond yield reduction
by M. Gerdts, W. C. Micke, D. Rough, K. W. Hench, L.T. Browne, G. S. Sibbett
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: Non-infectious bud failure (bf) is a genetic disorder of almonds that is present in a number of commercial varieties grown in California. Nonpareil, the industry's most important variety, is widely affected in certain sections of the San Joaquin and Sacramento valleys.
Abstract Not Available – First paragraph follows: Non-infectious bud failure (bf) is a genetic disorder of almonds that is present in a number of commercial varieties grown in California. Nonpareil, the industry's most important variety, is widely affected in certain sections of the San Joaquin and Sacramento valleys.
Replacing bud failure trees
by L. T. Browne, M. Gerdts, E. A. Yeary
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: The preceding article documents yield reductions in Nonpareil almond due to bud failure (BF). Since the yield data indicate crop reductions could potentially result in economic losses to almond growers, this study was developed to assist orchard managers in deciding what action to take when faced with BF. Three courses of action were evaluated: to maintain the BF trees, to graft, or to replant. Other alternatives, such as interplanting, are available in special cases but were not included in the study. The authors assume that normal non-BF trees will be obtained by grafting or replanting, and that a pathogen is not involved. The probability of meeting these assumptions is outlined in the previous articles.
Abstract Not Available – First paragraph follows: The preceding article documents yield reductions in Nonpareil almond due to bud failure (BF). Since the yield data indicate crop reductions could potentially result in economic losses to almond growers, this study was developed to assist orchard managers in deciding what action to take when faced with BF. Three courses of action were evaluated: to maintain the BF trees, to graft, or to replant. Other alternatives, such as interplanting, are available in special cases but were not included in the study. The authors assume that normal non-BF trees will be obtained by grafting or replanting, and that a pathogen is not involved. The probability of meeting these assumptions is outlined in the previous articles.

News and Opinion

Changing of the guard
by J.B. Kendrick
Full text HTML  | PDF  
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California Agriculture, Vol. 29, No.3

Cover:  Almond branch showing severe failure of leaf buds; flower buds have bloomed and set fruit.
March 1975
Volume 29, Number 3

Research articles

Anystid mite: Citrus thrips predator
by A. R. Mostafa, Paul DeBach, T. W. Fisher
| Full text HTML  | PDF  
An anystid mite, Anystis agilis (Banks) (Acarine: Anystidae) has been observed feeding on larval and adult citrus thrips, Scirtothrips citri (Moulton) in orange groves in River-side and Ventura counties. The mite has also been known to prey upon aphids and citrus red mites. This observation is important because citrus thrips is one of the two or three most important citrus pests in California, yet very little is known about its natural control. Since the population density of the citrus thrips varies widely from year to year and between different groves in the same year, natural factors not yet understood are operating to produce these observed fluctuations. Thus, this new ob-servation of A. agilis as a predator of citrus thrips is of considerable interest.
Nitrogen uptake in midwinter lettuce
by Keith S. Mayberry, Roy S. Rauschkolb
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: In the imperial valley it has been a common practice for growers to apply high rates of nitrogen in the form of calcium nitrate, in an attempt to increase the growth rate of head lettuce during cold weather and to improve external head color.
Abstract Not Available – First paragraph follows: In the imperial valley it has been a common practice for growers to apply high rates of nitrogen in the form of calcium nitrate, in an attempt to increase the growth rate of head lettuce during cold weather and to improve external head color.
Climate effects on grapefruit and lemons
by E. M. Nauer, J. H. Goodale, L. L. Summers, Walter Reuther
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: Two previous articles in California Agriculture (November 1972 and April 1974) have repofled some climate effects on oranges and mandarins. This third and final report covers data obtained on Frost Marsh nucellar and Redblush nucellar grapefruit harvested over a period of five crop seasons beginning with 1967-68. Eureka and Lisbon lemons were harvested over four seasons beginning with 1968-69.
Abstract Not Available – First paragraph follows: Two previous articles in California Agriculture (November 1972 and April 1974) have repofled some climate effects on oranges and mandarins. This third and final report covers data obtained on Frost Marsh nucellar and Redblush nucellar grapefruit harvested over a period of five crop seasons beginning with 1967-68. Eureka and Lisbon lemons were harvested over four seasons beginning with 1968-69.
Bud failure in almonds: Variability of bud failure in Nonpareil almonds
by D. E. Kester, Rachid Hellali, R. N. Asay
| Full text HTML  | PDF  
Noninfectious bud failure (BF) affects certain almond varieties and has become increasingly widespread in recent years.Symptoms are produced by failure of vegetative buds (particularly on middle and terminal portions of shoots) to grow in the spring. This is followed by vigorous wide-angled growth from surviving buds. In some trees, particularly when other symptoms are severe, bands of roughened bark appear on some branches. As this pattern of bud failure develops, BF trees develop wild, disoriented growth patterns and hence the disorder is frequently called “crazytop.”Early work on the BF problem developed the concept of increased BF incidence with successive vegetatively propagated generations. At that time BF was attributed to a ienetic disorder with unstable characteristics. Since then, observations suggest that mvironmental conditions affect the stability m d expression of BF. Vegetative propagations done on the premise that plants propagated from a common parent remain the same, but this premise is not fulfilled in the 3F disorder. In other cases where variations lave occurred after vegetative propagation, the problem has most often been attributable :o environmental influences, virus infections or mutations. However, variability of noninfectious BF cannot, at present, be directly accounted for by any one of these factors. This series of articles adds further information on he nature of BF and discusses selection for reedom from BF within the Nonpareil variety. It documents the impact of environment on BF potential and expression and provides lata on yield reduction due to BF. Finally, it iutlines a system of management decisions or orchardists faced with almond trees afected with BF.
Selection for freedom from bud failure
by D. E. Kester, R. N. Asay
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: Principle control measures for BF include standardization of nursery stock for low BF potential in susceptible varieties like Nonpareil or selection of varieties with no BF potential. Avoidance of susceptible varieties in localities with prolonged high summer temperature may be required, as better information on relative susceptibility is obtained.
Abstract Not Available – First paragraph follows: Principle control measures for BF include standardization of nursery stock for low BF potential in susceptible varieties like Nonpareil or selection of varieties with no BF potential. Avoidance of susceptible varieties in localities with prolonged high summer temperature may be required, as better information on relative susceptibility is obtained.
Almond yield reduction
by M. Gerdts, W. C. Micke, D. Rough, K. W. Hench, L.T. Browne, G. S. Sibbett
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: Non-infectious bud failure (bf) is a genetic disorder of almonds that is present in a number of commercial varieties grown in California. Nonpareil, the industry's most important variety, is widely affected in certain sections of the San Joaquin and Sacramento valleys.
Abstract Not Available – First paragraph follows: Non-infectious bud failure (bf) is a genetic disorder of almonds that is present in a number of commercial varieties grown in California. Nonpareil, the industry's most important variety, is widely affected in certain sections of the San Joaquin and Sacramento valleys.
Replacing bud failure trees
by L. T. Browne, M. Gerdts, E. A. Yeary
| Full text HTML  | PDF  
Abstract Not Available – First paragraph follows: The preceding article documents yield reductions in Nonpareil almond due to bud failure (BF). Since the yield data indicate crop reductions could potentially result in economic losses to almond growers, this study was developed to assist orchard managers in deciding what action to take when faced with BF. Three courses of action were evaluated: to maintain the BF trees, to graft, or to replant. Other alternatives, such as interplanting, are available in special cases but were not included in the study. The authors assume that normal non-BF trees will be obtained by grafting or replanting, and that a pathogen is not involved. The probability of meeting these assumptions is outlined in the previous articles.
Abstract Not Available – First paragraph follows: The preceding article documents yield reductions in Nonpareil almond due to bud failure (BF). Since the yield data indicate crop reductions could potentially result in economic losses to almond growers, this study was developed to assist orchard managers in deciding what action to take when faced with BF. Three courses of action were evaluated: to maintain the BF trees, to graft, or to replant. Other alternatives, such as interplanting, are available in special cases but were not included in the study. The authors assume that normal non-BF trees will be obtained by grafting or replanting, and that a pathogen is not involved. The probability of meeting these assumptions is outlined in the previous articles.

News and Opinion

Changing of the guard
by J.B. Kendrick
Full text HTML  | PDF  

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