|Crop Knowledge Master|
Macrosiphum euphorbiae (Thomas)
Jayma L. Martin Kessing, Educational Specialist
Ronald F.L. Mau, Extension Entomologist
Department of Entomology
Updated by: J.M. Diez April 2007
The potato aphid attacks over 200 plants including vegetable and ornamental crops as well as weeds. Cultivated food hosts include apple, bean, broccoli, burdock (gobo), cabbage, celery, Chinese broccoli, Chinese cabbage, corn, eggplant, ground cherry, lettuce, mustard cabbage, papaya, pea, pepper, potato, strawberry, sunflower, sweetpotato, tomato, turnip, white mustard cabbage and zucchini. Ornamental hosts are aster, Easter lily, gladiolus, iris and rose. Weed hosts, such as lamb's quarters, pig weed, ragweed, and shepherd's-purse serve as important reservoir hosts for the species.
Of North American origin, this aphid has a world wide distribution except for the Indian subcontinent. It was first reported in Hawaii in 1910, and is now present on Hawaii, Kauai, Maui and Oahu.
Aphids feed by sucking sap from their hosts. When aphid populations are large, feeding can cause plants to become deformed and the leaves curled and shriveled (Metcalf, 1962). Extensive damage can occur when aphid populations are large throughout the crop. This rarely happens in Hawaii because of natural enemies and the use of insecticides.
On lettuce, aphids are a problem for three reasons: they vector virus diseases, they can cause reduced or abnormal growth (Reinink and Dieleman, 1989).
On strawberries the presence of honeydew, cast skins or sooty mold makes them unmarketable since the fruit can't be washed because this would increase the incidence of disease and decrease shelf life (Trumble et. al., 1983).
On broccoli, this pest is usually present on the youngest and oldest leaves that have higher concentrations of nitrogen containing compounds.
Aphids vector plant viruses, and this activity potentially can result in greater losses than direct feeding damage. The potato aphid vectors over 40 non-persistent viruses and 5 persistent viruses. It is able to vector both P (PRSV-P) and W (PRSV-W) strains of Papaya Ringspot Virus. PRSV-P manifests on papaya. PRSV-W does not infect papaya, but does infect cucurbits and watermelon. PRSV-W is also called Watermelon Mosaic Virus 1 (WMV-1). This aphid also transmits Watermelon Mosaic Virus 2 (WMV-2).
Reproduction in Hawaii does not involve mating and egg laying. Females give birth to live female nymphs. As a consequence of this type of reproduction, populations are composed solely of females and there are no males present.
In temperate regions, these aphids overwinter during the egg stage. These eggs are pale green when first laid and turn shiny black in a few hours. In Hawaii, eggs are not produced by aphid females.
Immatures are elongated and paler than adults with a light covering of white-gray wax and a dark stripe running down their back.
When full grown, the potato aphid is nearly 1/8 inch long. Eyes are distinctly red and they have long slender cornicles extending from the abdomen. There are two color types, the pink form and the green form. Although the majority of the progeny from a green form parent is green and likewise for the pink form, both color forms are able to parent either color form, (Shull, 1925). Adults are usually without wings. Winged adults are developed in response to high population densities, decline of the host plant, and changes in environmental conditions. Winged individuals may be of either color form.
Each unmated female may give birth to 50 or more active nymphs within 2 weeks. A generation develops on potato every 2 or 3 weeks.
Aphids cluster in shaded areas on the leaves, stems, and blossoms of plants. The wingless aphids tend to fall to the ground when the plant is disturbed. Winged individuals disperse readily between crops.
When population densities are high, winged individuals are produced. These individuals emigrate to new hosts. The production of winged versus wingless individuals is dependent on the day length, parent type, "generation" and temperature (MacGillivary and Anderson, 1964). Winged, or alate, aphids are more common when the photoperiod is between 11-13 hours a day, the parent aphids are unwinged and the first "generation" of aphids under like environmental conditions, and the temperature ranges from 50û-70_ F (MacGillivary and Anderson, 1964).
Barlow (1962) reported that potato aphid populations have the capacity to increase in temperatures between 41û and 77û F. The optimum temperature for population increase for the potato aphid is 68û F (Barlow, 1962).
There are several factors that naturally control aphid populations. Many aphids are naturally controlled by predators, parasites and pathogens (Hagen and van den Bosch, 1968). High temperatures increase mortality (Walker, 1982). Heavy rainfall washes aphids off plants (Hughes, 1963; Maelzer, 1977), however, this mortality factor is small because aphids usually gather on the protected under surface of leaves where they are less likely to be washed off (Walker et. al., 1984).
Research on the characteristics of resistant tomato plants to the pink form of the potato aphid show that plants with long and dense hairs are less desirable under field conditions (Quiros et. al, 1977). The same study showed that susceptible tomato plants had higher sucrose, lower quinic acid, and higher alanine and tyrosine contents and a trend toward higher total free amino-acid concentration, they also were a unique source of 0-phosphoethanol amine (Quiros et. al, 1977).
Butterhead lettuce varieties are usually moderately to highly resistant to the potato aphid (Reinink and Dieleman, 1989). They feel this resistance may be passed on through selective breeding to the modern crisphead variety Marbello which is a cross of crisphead and butterhead lettuces.
Insecticidal soaps offer some control against aphids. Applications should be applied at regular intervals for maximum efficacy (Koehler et. al., 1983). Users should carefully consider the use of soaps. Excessive use can cause a drop in yield of the crop.
A chemical management program for strawberries was tested by Trumble et al. (1983). They found that a regular sampling plan of counting the number of aphids per plant may be used to determine when the potential damage levels reach a threshold. If aphid numbers per plant are low (less than 10), no chemicals are necessary and monitoring should continue; if they are above the threshold level (30 aphids per plant on 30% of plants in field), chemicals should be applied. Upon determining their thresholds, they found treatments could be based either on a regular sequential sampling plan or a check for presence/absence.
Barlow, C. A. 1962. The Influence of Temperature on the Growth of Experimental Populations of Myzus persicae (Sulzer) and Macrosiphium euphorbiae (Thomas) (Aphididae). Can. J. Zool. 40: 146-156.
Blackman, R. L. and V.F. Eastop. 1984. Macrosiphum euphorbiae (Thomas). pp. 296. Aphids on the World's Crops: An Identification and information Guide. John Wiley & Sons: Chichester, New York, Brisbane, Toronto, Singapore. 466 pages.
Higa, S. Y. and R. Namba. 1971. Vectors of the Papaya Mosaic Virus in Hawaii. Proc. Hawaiian Entomol. Soc. 21(1): 93-96.
Hughes, R. D. 1963. Population Dynamics of the Cabbage Aphid, Brevicoryne brassicae. J. Anim. Ecol. 32:393-424.
Koehler, C. S., L. W. Barclay and T. M. Kretchun. 1983. Pests in the Home Garden. California Agriculture. 37(9/10): 11-12.
MacGillivray, M. E. and G. B. Anderson. 1964. The Effect of Photoperiod and Temperature on the Production of Gamic and Agamic Forms in Macrosiphium euphorbiae (Thomas). Can. J. Zool. 42: 491-510.
Maelzer, D. A. 1977. The Biology and Main Causes of Changes in Numbers of the Rose Aphid, Macrosiphum rosae (L.) on Cultivated Roses in South Australia. Austral. J. Zool. 25: 269-284.
Metcalf, C. L., and W. P. Flint. 1962. Destructive and Useful Insects Their Habits and Control, Fourth Edition. Revised by: R. L. Metcalf. McGraw-Hill Book Company, Inc. New York, San Francisco, Toronto, London. pp. 646-647.
Purcifull, D., E. Hiebert and J. Edwardson. 1984a. Watermelon Mosaic Virus 2. CMI/AAB Descriptions of Plant Viruses No. 293 (No. 63 revised).
Purcifull, D., J. Edwardson, E. Hiebert, D. Gonsalves. 1984b. Papaya Ringspot Virus. CMI/AAB Descriptions of Plant Viruses, No. 292 (No. 84 revised).
Quiros, C. F., M. A. Stevens, C. M. Rick, M. L. Kok-Yokomi. 1977. Resistance in Tomato to the Pink Form of the Potato Aphid
(Macrosiphum euphorbiae Thomas): The Role of Anatomy, Epidermal Hairs, and Foliage Composition. J. Am. Hort. Soc. 102(2): 166-171.
Reinink, K and F. L. Dieleman. 1989. Resistance in Lettuce to the Leaf Aphids Macrosiphum euphorbiae and Uroleucon sonchi. Ann. Appl. Biol. 115(3): 489-498.
Shull, A. F. 1925. The Life Cycle of Macrosiphium solanifolii with Special Reference to the Genetics of Color. American Naturalist. 59(663): 289-310.
Trumble, J. T., E. R. Oatman, and V. Voth. 1983. Thresholds and Sampling for Aphids in Strawberries. California Agric. 37(11/12): 20-21.
Walker, G. P., L. R. Nault, and D.E. Simonet. 1984. Natural Mortality Factors Acting on Potato Aphid (Macrosiphum euphorbiae) Populations in Processing-Tomato Fields in Ohio. Environ. Entomol. 13(3): 724-732.
Walker, G. P. 1982. The Dispersion and Abundance of the Potato Aphid (Macrosiphum euphorbiae [Thomas]) on Tomato (Lycopersicon esculentum Mill.). Ph.D. Dissertation, Ohio State University, Wooster.
Zimmermann, E. C. 1948. Macrosiphum solanifoli (Ashmead). pp. 113. In Insects of Hawaii. A Manual of the Insects of the Hawaiian Islands, including Enumeration of the Species and Notes on Their Origin, Distribution, Hosts, Parasites, etc. Volume 5. Homoptera: Sternorhyncha. 464 pages.