Wikipedia

Potato leafhopper

Potato leafhopper (Empoasca fabae) belongs to family Cicadellidae and genus Empoasca within order Hemiptera.[1] In North America they are a serious agricultural pest.[2] Every year millions of dollars are lost from reduced crop yields and on pest management.[3] Crops that are impacted the most are potatoes, clover, beans, apples and alfalfa.[4]

Potato leafhopper
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Auchenorrhyncha
Family: Cicadellidae
Genus: Empoasca
Species:
E. fabae
Binomial name
Empoasca fabae
(Harris, 1841)
Empoasca fabae, potato leafhopper
Empoasca fabae, potato leafhopper, Size: 3.3 mm

Appearance edit

Adults have pale to iridescent green bodies with 6 or 8 white spots on their pronotum.[4] They have a distinctive white H shape mark between their head and wing base.[5] Their bodies are approximately 3 mm long and have on their front wings near its tip a crossvein.[4] Adults and nymphs move by hopping among host plants.[5] However, only adults can fly.[6]

Diet edit

They are able to feed and reproduce on at least 200 different plant species across twenty-six families.[1] In total herb genera represent 64% of their hosts.[7] Adults prefer to feed on the leaves and stems, while the nymphs prefer the leaves.[7] Their specialized mouth parts are able to pierce into the plant tissue and remove its sap.[8] The ability to inhabit a wide range of hosts is due to the variation in their feeding behaviors.[9]

Migration edit

Empoasca fabae is a seasonal migration species.[10] If they are flying at night, it takes two or three days to reach their summer destinations.[11] Research suggests that they are using winds as a passive means to help migrate.[10] The direction of the winds influence their distribution within their summer range.[10] Typically, the winds blow in a north-northeast direction towards Northern and Midwest United States.[10] Factors such as warm temperatures and lack of precipitation increases their range.[11] Cold temperatures, major precipitation, and unsuitable environmental conditions are factors that will stop migration to continue more north.[11] In late summer, cold fronts start to appear sending cues for them to leave.[10] As they leave they get caught up in these fronts which carry them south to southwest to their overwintering range.[10]

Habitat and range edit

Winter edit

Due to their inability to tolerate the cold winter temperatures they must migrate south.[10] Adults overwinter on hosts in the pine and mixed hardwood forests along the Gulf of Mexico and in the Southern United States.[12] Eastern Texas and Oklahoma, Virginia, Louisiana, Florida, Georgia, South and North Carolina, Alabama, Tennessee, Arkansas, and Mississippi, have documented populations.[12] Before migrating back to their summer range they change their hosts to herbaceous legumes then to new spring foliage of deciduous trees.[12]

Summer edit

Their summer range extends across the Midwest and eastern parts of Canada and the United States.[13] In Canada, they are found only in the Great Lakes region.[10] They are able to inhabit a wide range of habitats.[9] Only about 32% of individuals actually occupy croplands.[9] The remaining individuals will reside in fields, woodlands, scrublands, waste places, and parks.[9] Precipitation will deposit individuals upon plant hosts where they will quickly re-establish themselves.[14]

Development and reproduction edit

Diapause edit

Before migrating they mate and enter reproductive diapause.[12] Empoasca fabae begin to enter into reproductive dispause at the end of July.[15] The entire population remains in this state for its migration and overwintering period.[12] This diapause period ends from mid-January through February, and they begin to sexually mature.[12]

Egg laying edit

During the spring migration north, the majority of the individuals are females.[16] When they return if temperatures are above 10 °C they can start oviposition and populations grow and re-establish themselves.[17] Empoasca fabae arrives back to their summer ranges during April or early May depending on the location.[18]

During the summer months they can, on average, lay eggs over a span of 96 days.[19] Peak population densities occur during late May to late June.[8] Many overlapping generations appear.[8] After this their population densities begin to decline slowly.[18] Individuals have a tendency to aggregate as their populations increase.[18] At the end of the summer, individuals either die or migrate south.[20]

Eggs and hatchlings edit

Eggs are laid on their hosts; they are transparent and small in size.[5] Females will lay 2 or 3 eggs a day on the plant's stem and leaf veins.[21] The egg's incubation period ranges from 4 through 23 days, the hatchings are called nymphs.[19] New hatchlings are white in colour and develop their green colouring as they age.[19] The nymphs undergo five instars before becoming adults.[16] As they develop, they lose their skin and develop their wings.[5] Empoasca fabae develops into adults in 8 through 37 days.[19] Their entire lifecycle is one month long.[21]

As a pest edit

Hopperburn edit

The visually descriptive term hopperburn is used for a distinct type of damage on plants by E. fabae's feeding on its hosts.[16] As they feed their saliva mechanically injures the phloem and parenchyma cells.[2] The plant also suffers damage to its vascular cambium, and to its vascular bundles.[16] Within 24 hours of being infested, rates of photosynthesis, and transpiration are reduced, leaves accumulate starch, and transport of photoassimilates are reduced.[7]

The first symptoms of hopperburn is that a leaflet's margins start to curl up.[7] As a plant's infestation increases, its leaves cup downward, and they start to turn from green to yellow.[22] In severe infestations this leads to leaf necrosis in which the leaf margins and intervein areas turn brown.[22] Older plants completely lose their leaves.[3] Young plants display tip-wilting and will be stunted in height.[3] Plants that were damaged by stem feeding suffered more damage to their physiologies than those which were damaged by leaf eating.[7]

Research has shown that water-stressed plants increase nymph's development time.[6] This causes severe hopperburn due to the increase plant stress response.[21]

Economic impacts edit

Hopperburn leads to reduced plant growth and reproduction.[3] In some heavily infested fields up to 75% of the yield is lost, it depends on what stage of development the plants are in.[13] Obviously, this leads to reductions in crop yields and large economic losses.[3] For example, in 1988 the losses of alfalfa crops in Northeast United States ranged from $32-$66 per hectare.[23] The amount of crop damage is directly proportional to the population density.[13] Most crop damage comes from the future generations of the initial arrivals back to the summer range.[11]

Climate change edit

Research has indicated that over the last 62 years that they have been arriving back to their summer range earlier by ten days.[24] Warmer temperatures increases the time and speed of egg hatching and nymph development.[17] There is increasing concern that climate change will shift the overwintering and summer ranges more northward.[24] This will exacerbate the problem of pest management and increase economic losses. .[24]

Pest management edit

Usually, crop detection of E. fabae is too late as hopperburn is the first visual symptom of a major infestation.[21] Regular crop inspections with a sweep net are essential to help reduce massive economic losses.[21] Another visual cue is the death of leaves with small pits holes throughout them resulting from their eggs.[5] Host expansion is likely caused from the loss of natural resistance through extensive plant breeding.[1]

Currently, the only effective method that exists for controlling E. fabae's infestations is the heavy application of insecticides.[13] Short-lived insecticides such as carbaryl are commonly used; however they require costly reapplications.[14]

Research is indicating the possibility of being able to control populations by increasing E. fabae's natural enemies as part of pest management plan.[25] Percent mortality has been shown to be highest in individuals in younger instars.[15] Research has shown that natural resistance and pesticide use are just as effective, but neither is capable to fully contain populations.[26] To create more effective management programs and reduce pesticide use it is essential to understand their dispersion, temporal and spatial patterns.[18]

References edit

  1. ^ a b c ”Lamp, W., D., Miranda, L., Culler & Alexander, L. (2011) “Host Suitability and Gas Exchange Response of Grapevines to Potato Leafhopper (Hemiptera: Cicadellidae)”. Journal of Economic Entomology 104 (4): 1316–1322.
  2. ^ a b ”Delay, B., P, Mamidala, A, Wijeratne., S, Wijerante, O, Mittapalli, J, Wang., and Lamp, W. (2012). “Transcriptome analysis of the salivary glands of potato leafhopper, Empoasca fabae”. Journal of Insect Physiology 58 (12): 1626–1634.
  3. ^ a b c d e E.A. Backus; M.S. Serrano; C.M. Ranger (2005). "Mechanisms of Hopperburn: An Overview of Insect Taxonomy, Behavior, and Physiology". Annual Review of Entomology. 50 (1): 125–151. doi:10.1146/annurev.ento.49.061802.123310. PMID 15471532.
  4. ^ a b c "Bland R.G., Jaques H.E. (2010). How to Know the Insects 3rd Edition. Waveland Press Inc. p. 163.
  5. ^ a b c d e ”Dudley, J. (1921). “The Potato Leafhopper and its control”. United States Department of Agriculture: Farmers Bulletin 1225, 1–16.
  6. ^ a b ” Hoffman, G., D, Hogg, & Boush, M. (1991). “Potato Leafhopper (Homoptera: Cicadellidae) Life History Traits on Water-Stressed Alfalfa in the Early Regrowth and Bud Stage”. Environmental Entomology 20(4): 10581066.
  7. ^ a b c d e ”Lamp, W., Nielsen, G., Fuentes, C., & Quebedeaux, B. (2004) “Feeding Site Preference of Potato Leafhopper (Homoptera: Cicadellidae) on Alfalfa and its Effect on Photosynthesis”. Journal of Agricultural and Urban Entomology 21 (1): 25–38
  8. ^ a b c ”Potter, D., & Spicer, P. (1993). “Seasonal Phenology, Management, and Host Preferences of Potato Leafhopper on Nursery-Grown Maples” Journal of Environmental Horticulture 11(3): 101–106.
  9. ^ a b c d ” Lamp, W., G, Nielson., & Danielson, S. (1994). “Patterns among Host Plants of Potato Leafhopper, Empoasca fabae (Homoptera: Cicadellidae.” Journal of the Kansas Entomological Society 67(4): 354-368.
  10. ^ a b c d e f g h "Taylor, R., & Reling, D. (1986). Preferred Wind Direction of Long-Distance Leafhopper (Empoasca fabae) Migrants and its Relevance to the Return Migration of Small Insects. Journal of Animal Ecology 55(3): 1103–1114.
  11. ^ a b c d J.D. Carlson; M.E. Whalon; D.A. Landis & S.H. Gage (July 1992). "Springtime weather patterns coincident with long-distance migration of potato leafhopper into Michigan". Agricultural and Forest Meteorology. 59 (3–4): 183–206. Bibcode:1992AgFM...59..183C. doi:10.1016/0168-1923(92)90092-I.
  12. ^ a b c d e f ”Taylor, P., & Sheilds, E. (1995). “Phenology of Empoasca fabae (Harris) (Homoptera: Cicadellidae) in its Overwintering Area and Proposed Seasonal Phenology”. Environmental Entomology 24 (5): 1096–1108.
  13. ^ a b c d ”Medeiros, A., W, Tingey., & De Jong, W. (2004). “Mechanisms of Resistance to Potato Leafhopper, Empoasca fabae (Harris), in Potato”. American Journal of Potato Research 81(6): 431–441.
  14. ^ a b ”Van Timmeren, S., J, Wise, C, Vandervoort., & Isaacs, R. (2011). “Comparison of foliar and soil formulations of neonicotinoid insecticides for control of potato leafhopper, Empoasca fabae (Homoptera: Cicadellidae), in wine grapes.” Pest Management Science 67(5): 560–567.
  15. ^ a b ” Erlandson, W., & Obrycki, J. (2015). “Population Dynamics of Empoasca fabae (Hemiptera: Cicadellidae) in Central Iowa Alfalfa Fields.” Journal of Insect Science 15(1): 1-6.
  16. ^ a b c d ”Maletta, M., M, Henninger, & Holmstrom, K. (2006). “Potato Leafhopper Control and Plastic Mulch Culture in Organic Potato Production”. HortTechnology 16 (2): 199-204.
  17. ^ a b ”Sidumo, A., E, Sheilds., & Lembo, A. (2005). “Estimating the Potato Leafhopper Empoasca fabae (Homoptera: Cicadellidae) Overwintering Range and Spring Premigrant Development by Using Geographic Information System.” Journal of Economic Entomology 98 (3): 757–764.
  18. ^ a b c d ”Bentz, J., & Townsend, A. (2004). “Spatial and temporal patterns of abundance of the potato leafhopper among red maples.” Annals of Applied Biology 145(2): 157-164.
  19. ^ a b c d ”Poos, F. (1932). “Biology of the Potato Leafhopper, Empoasca Fabae (Harris), and Some Closely Related Species of Empoasca.” Journal of Economic Entomology 25(3): 639-646.
  20. ^ ”Taylor, P., E, Sheilds., M, Tauber., & Tauber, C. (1995). “Induction of Reproductive Diapause in Empoasca fabae (Homoptera: Cicadellidae) and Its Implications Regarding Southward Migration”. Environment Entomology 24 (5): 1086–1095.
  21. ^ a b c d e ”Townsend, L. (2012). “Potato Leafhoppers.” University of Kentucky. Version 2012.2. ENT facts http://www2.ca.uky.edu/entomology/entfacts/ef115.asp Retrieved 28 November 2015
  22. ^ a b "Murray, J., M, Paul., & Schaafma, A. (2001) “Determination of traits associated with leafhopper (Empoasca fabae and Empoasca kraemeri) resistance and dissection of leafhopper damage symptoms in the common bean (Phaseolus vulgaris)”. Annals of Applied Biology. 139(3): 319-327.
  23. ^ Lamp,W., Nielsen, G., & Dively, G. (1991)“Insect Pest-Induced Losses in Alfalfa: Patterns in Maryland and Implications for Management.” Journal of Economic Entomology 84(2): 610-618.
  24. ^ a b c ” Baker, M., P, Venugopal., & Lamp, W. (2015). “Climate Change and Phenology: Empoasca fabae (Hemiptera: Cicadellidae) Migration and Severity of Impact”. PLoS ONE 10 (5): 1–12
  25. ^ ”Erlandson, W., & Obrycki, J. (2010). “Predation of Immature and Adult Empoasca fabae (Harris) (Hemiptera: Cicadellidae) by Three Species of Predatory Insects.” Journal of the Kansas Entomological Society 83(1): 1-6.
  26. ^ Ghidiu, G., D, Douches., K, Flecher., & Coombs, J. (2011). “Comparing Host Plant Resistance, Engineered Resistance, and Insecticide Treatment for Control of Colorado Potato Beetle and Potato Leafhopper in Potatoes.” International Journal of Agronomy 11(6): 516–523
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