California Agriculture
California Agriculture
California Agriculture
University of California
California Agriculture

Archive

April 1977
Volume 31, Number 4

Peer-reviewed research and review articles

Insecticides evaluated for lettuce root aphid control
by Nick C. Toscano, Ken Kido, Marvin J. Snyder, Carlton S. Koehler, George C. Kennedy, Vahram Sevacherian
| Full text HTML  | PDF  
Insecticides applied to the primary host of lettuce root aphid- Lombardy poplar-controlled aphids before their main migration to nearby lettuce fields. Applying insecticides in lettuce fields gave inconclusive results.
Abstract Not Available – First paragraph follows: The lettuce root aphid, Pemphigus bursarius L., can cause considerable damage to crops of summer head lettuce. Its primary host is the Lombardy poplar, Populus italica var. nigra. The aphids, or “stem mothers,” which hatch in the spring from eggs that have overwintered on the poplar, cause hollow, flask-shaped galls to develop on the leaf petioles (fig. 1). The stem mother becomes enclosed within the gall, where it matures and gives rise to between 100 and 250 young.
Conservation irrigation of field crops: A drought-year strategy
by J. Ian Stewart
| Full text HTML  | PDF  
By making key decisions before planting, programming for minor water deficits, and irrigating more efficiently than usual, the grower can use the limited water available on the maximum acreage and still obtain good yields.
Abstract Not Available – First paragraph follows: To make the most efficient use of limited water supplies in the production of field crops, a sequence of key decisions must be made before planting. These decisions are particularly important in a drought year such as 1977 in California.
Nematicides improve sugar beet yields
by Demetrios G. Kontaxis, Ivan J. Thomason, Will Crites, Harold Lembright, Robert W. Hagemann
| Full text HTML  | PDF  
Treating sugar beet plots with fumigants or granular nematicides dramatically increased yields over those from check plots, but treatment would be unprofitable at current sugar prices.
Nematicides dramatically increased yields but not enough to justify costs at current sugar prices.
Midges plague lakeside dwellers
by Robert M. Boardman
| Full text HTML  | PDF  
Researchers expect to find chemical and biological means of reducing the large swarms of midges that breed in the warm, shallow, artificial lakes in new southern California housing developments, but residents will have to tolerate some midges.
Abstract Not Available – First paragraph follows: A new phenomenon in California home ownership has led to an emerging problem of pestiferous insects: City dwellers moving into new housing developments built around man-made recreational lakes have been met with swarms of chironomid midges.
Glandless acala cotton: More susceptible to insects
by John H. Benedict, Thomas F. Leigh, Ward Tingey, Angus H. Hyer
| Full text HTML  | PDF  
Glandless Acala cotton, lacking the pigment glands that produce gossypol, a substance toxic to most plant-feeding animals, is more susceptible than glanded cotton to damage by lygus bugs. As a result, cotton yields are reduced.
Abstract Not Available – First paragraph follows: Commercially grown Acala cottons (Gossypium hirsutum L.), like most other species of the genus Gossypium, have evolved an effective chemical resistance that deters most plant-feeding animals. The biologically toxic component is a group of related, secondary plant metabolites known as terpenoids. Gossypol, the best known of these terpenoids, is a polyphenolic yellow pigment closely associated with the epidermal glands present on all aerial plant parts as well as in the cottonseed. Most commercial cottonseed contains about 1 percent gossypol, depending on variety and environmental conditions. Expensive chemical and physical procedures are used to remove gossypol from cottonseed products destined for use as food for non-ruminant animals.
Preventing enzymatic softening of canned apricots
by Noel F. Sommer, Jack R. Buchanan, Robert J. Fortlage, F. Gordon Mitchell
| Full text HTML  | PDF  
Softening of canned apricots by heat-tolerant pectolytic enzymes of fungal origin was prevented for over a year by dipping the fruit halves in a cold dilute lye solution and rinsing before canning.
Abstract Not Available – First paragraph follows: Canned, unpeeled apricot halves are subject to softening disorders, which destroy the integrity of the fruit flesh. When the cans are opened, one, a few, or all of the halves may be completely macerated, or they may appear normal but disintegrate upon handling. The inability to detect the problem before the can is opened results in a significant number of dissatisfied customers, even if the fraction of affected cans is small.
Thinning desertgold peaches increases fruit size
by Dean D. Halsey
| Full text HTML  | PDF  
Thinning with thiourea sprays at bud-swell resulted in larger fruit at harvest, as did shortening fruit-bearing branches after standard pruning, hand thinning flowers at bloom, and girdling.
Abstract Not Available – First paragraph follows: Peach harvest begins about April 25 and continues for two weeks in the Coachella Valley. This district produces the first peach fruit of the season from California, but it is closely followed by other districts. Because the first shipments reaching market receive favorable prices, it is important to Coachella Valley growers that their peaches reach optimum market quality, particularly acceptable fruit size, as early as possible.
Straw: Low-cost feed but not least cost
by John L Hull, John R. Dunbar
| Full text HTML  | PDF  
Low-cost barley and wheat straws fed to steers in experimental growing rations were not a cheap source of nutrients, especially energy, and therefore did not provide least-cost gains.
Abstract Not Available – First paragraph follows: Whenever grain and hay prices are high, there is renewed interest in feeding cereal straws to growing cattle as a possible method of cutting costs. Feeding trials were conducted using cereal straws in rations formulated by a computer least-cost ration program. The growing phase compared barley straw with wheat straw with a further comparison of cottonseed meal (CSM) and urea as the nitrogen source. A standard ration was fed during the fattening phase.
Chemical defoliation of fruit trees
by Marvin H. Gerdts, Gary L. Obenauf, James H. LaRue, George M. Leavitt
| Full text HTML  | PDF  
Earlier pruning of peach, nectarine, and plum trees would permit better use of the labor force. In defoliant testing, D-WK, alone and in combination with zinc sulfate, induced good defoliation with few adverse effects.
Abstract Not Available – First paragraph follows: Trees in most mature peach, nectarine, and plum orchards in the southern San Joaquin Valley cease growth by early to mid-October. Because the foliage often persists on the trees for another three to five weeks and interferes with the pruner's vision, it is impractical to start annual pruning immediately. Thus, any means of stimulating defoliation in mid-October that would allow an earlier start on pruning could become an important factor for progressive farm labor managers. Under normal conditions, many farm laborers are idle from mid-October through mid-November, because harvest of most other crops is nearly completed. The availability of defoliated trees by mid-October would provide work when the unemployment rate is high and would extend the period over which dormant pruning could be accomplished.

News and opinion

Research ready for the problem
by J. B. Kendrick
Full text HTML  | PDF  
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April 1977
Volume 31, Number 4

Peer-reviewed research and review articles

Insecticides evaluated for lettuce root aphid control
by Nick C. Toscano, Ken Kido, Marvin J. Snyder, Carlton S. Koehler, George C. Kennedy, Vahram Sevacherian
| Full text HTML  | PDF  
Insecticides applied to the primary host of lettuce root aphid- Lombardy poplar-controlled aphids before their main migration to nearby lettuce fields. Applying insecticides in lettuce fields gave inconclusive results.
Abstract Not Available – First paragraph follows: The lettuce root aphid, Pemphigus bursarius L., can cause considerable damage to crops of summer head lettuce. Its primary host is the Lombardy poplar, Populus italica var. nigra. The aphids, or “stem mothers,” which hatch in the spring from eggs that have overwintered on the poplar, cause hollow, flask-shaped galls to develop on the leaf petioles (fig. 1). The stem mother becomes enclosed within the gall, where it matures and gives rise to between 100 and 250 young.
Conservation irrigation of field crops: A drought-year strategy
by J. Ian Stewart
| Full text HTML  | PDF  
By making key decisions before planting, programming for minor water deficits, and irrigating more efficiently than usual, the grower can use the limited water available on the maximum acreage and still obtain good yields.
Abstract Not Available – First paragraph follows: To make the most efficient use of limited water supplies in the production of field crops, a sequence of key decisions must be made before planting. These decisions are particularly important in a drought year such as 1977 in California.
Nematicides improve sugar beet yields
by Demetrios G. Kontaxis, Ivan J. Thomason, Will Crites, Harold Lembright, Robert W. Hagemann
| Full text HTML  | PDF  
Treating sugar beet plots with fumigants or granular nematicides dramatically increased yields over those from check plots, but treatment would be unprofitable at current sugar prices.
Nematicides dramatically increased yields but not enough to justify costs at current sugar prices.
Midges plague lakeside dwellers
by Robert M. Boardman
| Full text HTML  | PDF  
Researchers expect to find chemical and biological means of reducing the large swarms of midges that breed in the warm, shallow, artificial lakes in new southern California housing developments, but residents will have to tolerate some midges.
Abstract Not Available – First paragraph follows: A new phenomenon in California home ownership has led to an emerging problem of pestiferous insects: City dwellers moving into new housing developments built around man-made recreational lakes have been met with swarms of chironomid midges.
Glandless acala cotton: More susceptible to insects
by John H. Benedict, Thomas F. Leigh, Ward Tingey, Angus H. Hyer
| Full text HTML  | PDF  
Glandless Acala cotton, lacking the pigment glands that produce gossypol, a substance toxic to most plant-feeding animals, is more susceptible than glanded cotton to damage by lygus bugs. As a result, cotton yields are reduced.
Abstract Not Available – First paragraph follows: Commercially grown Acala cottons (Gossypium hirsutum L.), like most other species of the genus Gossypium, have evolved an effective chemical resistance that deters most plant-feeding animals. The biologically toxic component is a group of related, secondary plant metabolites known as terpenoids. Gossypol, the best known of these terpenoids, is a polyphenolic yellow pigment closely associated with the epidermal glands present on all aerial plant parts as well as in the cottonseed. Most commercial cottonseed contains about 1 percent gossypol, depending on variety and environmental conditions. Expensive chemical and physical procedures are used to remove gossypol from cottonseed products destined for use as food for non-ruminant animals.
Preventing enzymatic softening of canned apricots
by Noel F. Sommer, Jack R. Buchanan, Robert J. Fortlage, F. Gordon Mitchell
| Full text HTML  | PDF  
Softening of canned apricots by heat-tolerant pectolytic enzymes of fungal origin was prevented for over a year by dipping the fruit halves in a cold dilute lye solution and rinsing before canning.
Abstract Not Available – First paragraph follows: Canned, unpeeled apricot halves are subject to softening disorders, which destroy the integrity of the fruit flesh. When the cans are opened, one, a few, or all of the halves may be completely macerated, or they may appear normal but disintegrate upon handling. The inability to detect the problem before the can is opened results in a significant number of dissatisfied customers, even if the fraction of affected cans is small.
Thinning desertgold peaches increases fruit size
by Dean D. Halsey
| Full text HTML  | PDF  
Thinning with thiourea sprays at bud-swell resulted in larger fruit at harvest, as did shortening fruit-bearing branches after standard pruning, hand thinning flowers at bloom, and girdling.
Abstract Not Available – First paragraph follows: Peach harvest begins about April 25 and continues for two weeks in the Coachella Valley. This district produces the first peach fruit of the season from California, but it is closely followed by other districts. Because the first shipments reaching market receive favorable prices, it is important to Coachella Valley growers that their peaches reach optimum market quality, particularly acceptable fruit size, as early as possible.
Straw: Low-cost feed but not least cost
by John L Hull, John R. Dunbar
| Full text HTML  | PDF  
Low-cost barley and wheat straws fed to steers in experimental growing rations were not a cheap source of nutrients, especially energy, and therefore did not provide least-cost gains.
Abstract Not Available – First paragraph follows: Whenever grain and hay prices are high, there is renewed interest in feeding cereal straws to growing cattle as a possible method of cutting costs. Feeding trials were conducted using cereal straws in rations formulated by a computer least-cost ration program. The growing phase compared barley straw with wheat straw with a further comparison of cottonseed meal (CSM) and urea as the nitrogen source. A standard ration was fed during the fattening phase.
Chemical defoliation of fruit trees
by Marvin H. Gerdts, Gary L. Obenauf, James H. LaRue, George M. Leavitt
| Full text HTML  | PDF  
Earlier pruning of peach, nectarine, and plum trees would permit better use of the labor force. In defoliant testing, D-WK, alone and in combination with zinc sulfate, induced good defoliation with few adverse effects.
Abstract Not Available – First paragraph follows: Trees in most mature peach, nectarine, and plum orchards in the southern San Joaquin Valley cease growth by early to mid-October. Because the foliage often persists on the trees for another three to five weeks and interferes with the pruner's vision, it is impractical to start annual pruning immediately. Thus, any means of stimulating defoliation in mid-October that would allow an earlier start on pruning could become an important factor for progressive farm labor managers. Under normal conditions, many farm laborers are idle from mid-October through mid-November, because harvest of most other crops is nearly completed. The availability of defoliated trees by mid-October would provide work when the unemployment rate is high and would extend the period over which dormant pruning could be accomplished.

News and opinion

Research ready for the problem
by J. B. Kendrick
Full text HTML  | PDF  

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