California Agriculture
California Agriculture
California Agriculture
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California Agriculture

Archive

June 1977
Volume 31, Number 6

Peer-reviewed research and review articles

Machine harvesting fresh market onions
by Hunter Johnson, Joseph H. Chesson, Keith S. Mayberry, Robert G. Curley, Clay R. Brooks
| Full text HTML  | PDF  
Equipment consisting of an onion topper-undercutter and a bulb-trimming device showed promise in a 1975-76 study. Bulk curing systems tested at the same time also gave good results.
Abstract Not Available – First paragraph follows: Fresh market onions traditionally have been harvested by hand throughout the nation. A tractor-drawn horizontal blade severs the root system just below the bulbs; then tops and roots are clipped off with hand shears. The bulbs are stored in the field in burlap bags for a few days to cure. Many attempts have been made to mechanize topping and clipping, but, although some efforts have been moderately successful, none are used in California today. The principal reasons have been either damage to the bulbs or the inability of the equipment to remove tops and roots to market standards as capably as removal by hand.
Copper-streptomycin sprays control pear blossom blast
by Richard S. Bethell, Joseph M. Ogawa, W. Harley English, Robert R. Hansen, Billy T. Manji, Frank J. Schick
| Full text HTML  | PDF  
Cold, wet weather favors development of blast. In a 1976 study, bac-terially caused blast of pear blossoms was controlled with a copper spray applied in the delayed dormant period followed by a streptomycin spray at the start of bloom.
Abstract Not Available – First paragraph follows: Blasting of flower is an occasional problem in California pear orchards. Three common causes of blasted blossoms are boron deficiency, lack of winter chilling, and bacterial infection caused by Pseudomonas syringae van Hall. Bacterial blast is the most damaging and can reduce crops so severely they become unprofitable to harvest.
Chlormequat doubles yield of Malvasia bianca grapes
by William L. Peacock, Frederik L. Jensen
| Full text HTML  | PDF  
In 1976 trials in the San Joaquin Valley, a prebloom spray of the growth regulator chlormequat more than doubled the yield of Malvasia bianco, a muscat-type wine grape variety.
The growth regulator increased yield by 20 pounds per vine, primarily by improving berry set.
Evaluating pink bollworm control
by Robert A. VanSteenwyker, Gregory R. Ballrr, Nick C. Toscano, Harold T. Reynolds
| Full text HTML  | PDF  
Inspection of 14- to 21-day-old cotton bolls is the best means of evaluating pink bollworm control programs. With practice, such bolls can be identified in the field by their moisture, their lint development, and the absence of bollworm exit holes.
With experience, field workers can identify cotton bolls that are at the right stage of development for evaluation of control measures.
Beet curly top virulence increased
by Andrew C. Magyarosy, James E. Duffus
| Full text HTML  | PDF  
A study of curly top epidemiology in San Joaquin Valley sugar beet fields and in the foothills has shown that recent virus isolates are more virulent than those collected 20 years ago.
Recent curly top isolates from San Joaquin Valley sugar beet fields and the foothills are more virulent than those collected in the 1950s and 1960s. The beet leafhopper (showm below, 48 times life size) carries the disease between crops and weed plants.
Beet leafhopper transmits virescence of periwinkle
by George N. Oldfield, George H. Kaloostian, Harold D. Pierce, Andrew L. Granett, Edmond C. Calavan
| Full text HTML  | PDF  
The beet leafhopper, vector of curly top of sugar beets, naturally harbors an agent, apparently a mycoplasma-like organism, that causes virescence of periwinkle plants.
Photo above shows healthy periwinkle on left and virescence-affected periwinkle on right; plant on right was exposed to beet leafhopper (Circulifer tenellus) that had previously fed on another virescence-affected periwinkle. Photo below shows periwinkle plant that developed virescence after exposure to infective beet leafhopper; not variation in severity of symphotoms.
Tobacco budworm invades Imperial Valley cotton
by Rajinder K. Sharma, Nick C. Toscano, Harold T. Reynolds, Ken Kido, Ralph M. Hannibal, William M. Quillman
| Full text HTML  | PDF  
Tobacco budworm was found in Imperial Valley cotton in 1972, and surveys have since revealed large populations in late-season cotton. Among insecticides tested for budworm control, synthetic pyrethroids look the most promising.
Changes in production practices, as well as insecticides, should help control destructive budworm populations that have developed in late-season cotton.
Ethephon hastens ripening of Japanese plums
by George M. Leavitt, Marvin H. Gerdts, Gary L. Obenauf, F. Gordon Mitchell, Harry Andris
| Full text HTML  | PDF  
Preharvest applications of the growth regulator ethephon hastened skin color changes and flesh softening of Japanese plums but did not affect soluble solids accumulation before harvest. Postharvest ripening rates were not affected.
Abstract Not Available – First paragraph follows: Reported effects of the growth regulator ethephon on fruit maturity in many crops include earlier skin color changes, earlier flesh softening, and occasional increases in soluble solids. In 1975, preharvest ethephon applications on Japanese plum (Prunus salicina) were evaluated for their influence on fruit maturation and postharvest ripening.

News and opinion

Social impact of agricultural research
by J. B. Kendrick
Full text HTML  | PDF  
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June 1977
Volume 31, Number 6

Peer-reviewed research and review articles

Machine harvesting fresh market onions
by Hunter Johnson, Joseph H. Chesson, Keith S. Mayberry, Robert G. Curley, Clay R. Brooks
| Full text HTML  | PDF  
Equipment consisting of an onion topper-undercutter and a bulb-trimming device showed promise in a 1975-76 study. Bulk curing systems tested at the same time also gave good results.
Abstract Not Available – First paragraph follows: Fresh market onions traditionally have been harvested by hand throughout the nation. A tractor-drawn horizontal blade severs the root system just below the bulbs; then tops and roots are clipped off with hand shears. The bulbs are stored in the field in burlap bags for a few days to cure. Many attempts have been made to mechanize topping and clipping, but, although some efforts have been moderately successful, none are used in California today. The principal reasons have been either damage to the bulbs or the inability of the equipment to remove tops and roots to market standards as capably as removal by hand.
Copper-streptomycin sprays control pear blossom blast
by Richard S. Bethell, Joseph M. Ogawa, W. Harley English, Robert R. Hansen, Billy T. Manji, Frank J. Schick
| Full text HTML  | PDF  
Cold, wet weather favors development of blast. In a 1976 study, bac-terially caused blast of pear blossoms was controlled with a copper spray applied in the delayed dormant period followed by a streptomycin spray at the start of bloom.
Abstract Not Available – First paragraph follows: Blasting of flower is an occasional problem in California pear orchards. Three common causes of blasted blossoms are boron deficiency, lack of winter chilling, and bacterial infection caused by Pseudomonas syringae van Hall. Bacterial blast is the most damaging and can reduce crops so severely they become unprofitable to harvest.
Chlormequat doubles yield of Malvasia bianca grapes
by William L. Peacock, Frederik L. Jensen
| Full text HTML  | PDF  
In 1976 trials in the San Joaquin Valley, a prebloom spray of the growth regulator chlormequat more than doubled the yield of Malvasia bianco, a muscat-type wine grape variety.
The growth regulator increased yield by 20 pounds per vine, primarily by improving berry set.
Evaluating pink bollworm control
by Robert A. VanSteenwyker, Gregory R. Ballrr, Nick C. Toscano, Harold T. Reynolds
| Full text HTML  | PDF  
Inspection of 14- to 21-day-old cotton bolls is the best means of evaluating pink bollworm control programs. With practice, such bolls can be identified in the field by their moisture, their lint development, and the absence of bollworm exit holes.
With experience, field workers can identify cotton bolls that are at the right stage of development for evaluation of control measures.
Beet curly top virulence increased
by Andrew C. Magyarosy, James E. Duffus
| Full text HTML  | PDF  
A study of curly top epidemiology in San Joaquin Valley sugar beet fields and in the foothills has shown that recent virus isolates are more virulent than those collected 20 years ago.
Recent curly top isolates from San Joaquin Valley sugar beet fields and the foothills are more virulent than those collected in the 1950s and 1960s. The beet leafhopper (showm below, 48 times life size) carries the disease between crops and weed plants.
Beet leafhopper transmits virescence of periwinkle
by George N. Oldfield, George H. Kaloostian, Harold D. Pierce, Andrew L. Granett, Edmond C. Calavan
| Full text HTML  | PDF  
The beet leafhopper, vector of curly top of sugar beets, naturally harbors an agent, apparently a mycoplasma-like organism, that causes virescence of periwinkle plants.
Photo above shows healthy periwinkle on left and virescence-affected periwinkle on right; plant on right was exposed to beet leafhopper (Circulifer tenellus) that had previously fed on another virescence-affected periwinkle. Photo below shows periwinkle plant that developed virescence after exposure to infective beet leafhopper; not variation in severity of symphotoms.
Tobacco budworm invades Imperial Valley cotton
by Rajinder K. Sharma, Nick C. Toscano, Harold T. Reynolds, Ken Kido, Ralph M. Hannibal, William M. Quillman
| Full text HTML  | PDF  
Tobacco budworm was found in Imperial Valley cotton in 1972, and surveys have since revealed large populations in late-season cotton. Among insecticides tested for budworm control, synthetic pyrethroids look the most promising.
Changes in production practices, as well as insecticides, should help control destructive budworm populations that have developed in late-season cotton.
Ethephon hastens ripening of Japanese plums
by George M. Leavitt, Marvin H. Gerdts, Gary L. Obenauf, F. Gordon Mitchell, Harry Andris
| Full text HTML  | PDF  
Preharvest applications of the growth regulator ethephon hastened skin color changes and flesh softening of Japanese plums but did not affect soluble solids accumulation before harvest. Postharvest ripening rates were not affected.
Abstract Not Available – First paragraph follows: Reported effects of the growth regulator ethephon on fruit maturity in many crops include earlier skin color changes, earlier flesh softening, and occasional increases in soluble solids. In 1975, preharvest ethephon applications on Japanese plum (Prunus salicina) were evaluated for their influence on fruit maturation and postharvest ripening.

News and opinion

Social impact of agricultural research
by J. B. Kendrick
Full text HTML  | PDF  

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