Occurrence Of Aphids Research Articles

Development and Estimation of Aphid Populations Infesting Annual Winter Plantings of Strawberries in California

Temporal occurrence and sampling of aphids infesting fresh market strawberries were investigated in two successive annual winter plantings in Orange County, Calif. Chaetosiphon fragaefolii (Cockerell) was the dominant species as well as the primary cause of contamination. Aphis gossypii Glover was also a contaminant, but did not reach population densities as high as C. fragaefolii. Myzus persicae (Sulzer) and Macrosiphum euphorbiae (Thomas) were less common and were of minor importance. Aphid densities in excess of a log (x + 1) value of 1.5 (30.6 aphids) per plant resulted in contaminated fruit. Populations of C. fragaefolii on the youngest or oldest leaves co-varied with total populations, but this technique was not reliable for the other species. A binomial sampling plan based on the presence or absence of aphid infestations on the oldest trifoliate leaf per plant provided an efficient and conservative estimate for determining when pesticide applications are necessary.

Temporal Occurrence, Sampling, and Within-Field Distribution of Aphids on Broccoli in Coastal California1

Aphid occurrence, population dynamics, and sampling procedures were studied in three consecutive broccoli plantings in southern California. Myzus persicae (Sulzer) was dominant during the fall and spring, and Brevicoryne brassicae (L) was prevalent in winter. B. brassicae was the primary aphid contaminant of broccoli heads in all crops. Hyadaphis erysimi (Kaltenbach) and Macrosiphum euphorbiae (Thomas) occurred at low population levels and were of minor importance. Aphid distribution was aggregated when densities were low [log (x + 1) <1.0 per plant] but became random as populations increased. Sampling procedures based on 10-plant samples were useful in estimating aphid population when densities exceeded a log (x + 1) value of 0.65 per plant. Aphid parasitization did not exceed 6% of available hosts in any planting and was not a major mortality factor.

イネ科飼料作物ソルゴーを加害するヒエノアブラムシの生態 (第5報) 刈取時期および播種密度の違いと寄生消長

Seasonal abundance of the aphid, Longiunguis sacchari (ZEHNTNER), on sorghums cultivated under different harvesting schedule has been surveyed since 1974. Sorghums were sown at two or three different periods every year and harvested twice a year in summer and autumn, depending on the sowing time. The aphid populations were consistently most numerous in mid-August and mid- or late October, irrespective of sowing time of sorghums. When the 1st and 2nd harvests of sorghums were done earlier than each peak of aphid populations, the subsequent infestations could be avoided. In order to clarify the effects of plant populations on the aphid occurrence, sorghums were cultivated at 35, 50 and 70 cm wide in row spacing and the population increase of the aphids was surveyed. The results showed that the aphid densities tended to be higher with decreasing plant populations.

Properties and isolates of barley yellow dwarf virus

SUMMARYBarley yellow dwarf virus is persistently transmitted by a number of aphid species of which three, Rhopalosiphum padi, Sitobion avenae and Metopolophium dirhodum, are common in most years. Other aphids may be locally important. Isolates of the virus differ in their virulence and geographical distribution and are not transmitted equally well by all aphid vectors. Isolates with similar properties are grouped into strains according to their transmission by vectors and their severity. Changes in strain and aphid occurrence from year to year alter the incidence of virus and its effect on yield. These changes emphasize the need for detailed knowledge of cereal aphid biology and epidemiology of BYDV before effective control can be used.

Occurrence of aphid, diamondback moth, and cabbage sawfly, and repellent effect in the plastic mulching radish

Occurrence of aphid, diamondback moth, and cabbage sawfly, and repellent effect in the plastic mulching radish

Survey methods on the occurrence of aphids on radish

Survey methods on the occurrence of aphids on radish

Aphid trapping in Victoria. I. The seasonal occurrence of aphids in three localities and a comparision of two trapping methods

Information about the seasonal occurrence and peaks of activity of winged aphid species was obtained by trapping during a period of 15 months at three locations within 45 miles of Melbourne. Most species were caught in greatest numbers during either the spring or the autumn. Species such as Myzus persicae (Sulz.) and Brevicoryne brassicae (L.) were caught throughout the year. Cavariella aegopodii (Scop.) was trapped only in cool weather, while Aploneura lentisci (Pass.) was caught only in warm weather. Water-filled yellow trays were very efficient for trapping many species, but a wind-vane sticky trap caught more of some species, including the grass-feeding aphids, than did the yellow tray.

Biology of Cereal and Grass Aphids in Wisconsin (Homoptera)

Research was conducted on the biology of cereal and grass aphids in the Madison area during 1957-59 in connection with epidemiological investigations of the barley yellow dwarf virus (BYDV). It becomes of increasing importance to know more about these aphids as potential vectors of the virus. Information was needed on the taxonomy, biology and ecology of the vector population to better understand the complex interactions between vector and virus. Two methods were used to obtain data on the occurrence and abundance of aphids. The conventional method of studying aphid populations on host plants was supplemented with intensive research on air-borne aphids, using the yellow-pan water trap developed by Moericke (1951), and the wind trap described by Shands (1942). These traps are shown in Fig. 1. The species of aphids were identified according to keys of Palmer (1952). Names of genera as used in Europe have been indicated in parentheses. In the following report the various forms in the life cycle are referred to as fundatrices (on the winter host), fundatrigenae (produced by fundatrices, the alates of this generation migrate to summer hosts), virginoparae (both apterous and alate individuals on snmmer hosts), and gynoparae (alates migrate from summer hosts to winter hosts).

Spotted Alfalfa Aphid Occurrence on Seedling Alfalfa as Influenced by Systemic Insecticides and Varieties1

Journal Article Spotted Alfalfa Aphid Occurrence on Seedling Alfalfa as Influenced by Systemic Insecticides and Varieties Get access R. C. Dobson, R. C. Dobson Search for other works by this author on: Oxford Academic PubMed Google Scholar J. G. Watts J. G. Watts Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 50, Issue 2, 1 April 1957, Pages 132–135, https://doi.org/10.1093/jee/50.2.132 Published: 01 April 1957