Cotton aphid – Aphis gossypii

Cotton Aphid, or Aphis gossypii, is one of the more common insect pests found in almost all vegetable crops and gardens. They vary significantly in body size and color (from bright yellow, green and dirty brown olive), and adults may have transparent wings or wingless.

Damage cause by Cotton Aphids

Cotton aphid infestations may result in wilting, but this damage is usually not of great concern. The leaves are stunted and distorted and often curl downwards. The upper surface of the leaves are usually sticky and a black moldy growth appears at a later stage. Research indicates that early season infestations may delay maturity, but usually does not result in yield loss unless other factors are also present that enhance the injury. More importantly, these aphids vector diseases such as mosaic and tomato yellow top.

Control of Cotton Aphids

The parasitic wasp Lysiphlebus testaceipes¹Jamie E. Hopkinson, Myron P. Zalucki, David A.H. Murray, Host selection and parasitism behavior of Lysiphlebus testaceipes: Role of plant, aphid species and instar, Biological Control, Volume 64, Issue 3, 2013, Pages 283-290, ISSN 1049-9644, https://doi.org/10.1016/j.biocontrol.2012.11.016 and a group of aphid predators such as lady beetles (Hippodemia convergens & Coccinella novemnotata franciscana)²Mary Louise Flint, Steve H. Dreistadt, Interactions among convergent lady beetle (Hippodamia convergens) releases, aphid populations, and rose cultivar, Biological Control, Volume 34, Issue 1, 2005, Pages 38-46, ISSN 1049-9644, https://doi.org/10.1016/j.biocontrol.2005.03.019. as well as the larvae of syrphid flies can limit the spread of cotton aphids. However, if you don’t have a strong presence of predatory insects in your environment, chemical control will be necessary. Note that the use of pyrethroid can stimulate the population growth of aphids.

According to the Enemies Hypothesis by Russell (1989)³Russell, Edmund P. “Enemies hypothesis: a review of the effect of vegetational diversity on predatory insects and parasitoids.” Environmental entomology 18.4 (1989): 590-599. & Sheehan (1986)⁴Sheehan, William. “Response by specialist and generalist natural enemies to agroecosystem diversification: a selective review.” Environmental Entomology 15.3 (1986): 456-461., the populations of natural enemies will be higher in diverse habitats. This is because there are more predators and higher number of micro-habitats to breed. So any mono cropping farming practice will automatically increase pest populations and reduce predator populations. That is why it is such a good thing to grow plants that predators feed on next to fields so their populations can be maintained.

Monitoring:

The easiest way to measure the population growth is by yellow sticky traps or similar products. However, it is also good to know when to expect higher population growth and when aphids are not that active. The ability of aphids to produce an abundance of offspring increased from 36 larvae/female at 10°C to 76 larvae/female at 30°C⁵Kocourek, F., Havelka, J., Beránková, J. and Jaroŝik, V. (1994), Effect of temperature on development rate and intrinsic rate of increase of Aphis gossypii reared on greenhouse cucumbers. Entomologia Experimentalis et Applicata, 71: 59-64. https://doi.org/10.1111/j.1570-7458.1994.tb01769.x

Biological control of greenhouse aphids.

Effective biological control of aphids in greenhouses is doubtful. Reducing nitrogen fertilization can reduce aphid population increase to an extent, thereby increasing biological control effectiveness⁶Rabasse, J.M., van Steenis, M.J. (1999). Biological Control of Aphids. In: Albajes, R., Lodovica Gullino, M., van Lenteren, J.C., Elad, Y. (eds) Integrated Pest and Disease Management in Greenhouse Crops. Developments in Plant Pathology, vol 14. Springer, Dordrecht. https://doi.org/10.1007/0-306-47585-5_16. It is still not the sole means of control and must be combined with IPM for the grower to be economically sustainable. However, it does not mean biological control does not help. You have to identify the specie of aphids you want to control biologically as it is not just a question of randomly releasing predators into the greenhouse. For instance, the greenhouse release of parasitoids Aphidius matricariae would be best timed to coincide with the period when third and fourth nymphal instars of cotton aphid are most abundant⁷Ali Asghar Talebi1, Abbas Ali Zamani1, Yaghoub Fathipour1, Valiollah Baniameri2, Katayun Kheradmand1 and Mostafa Haghani 11 Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box: 14115-336, Tehran, 2Department of Agricultural Entomology, Plant Pests & Diseases Research Institute, P. O. Box: 1454-19395, Tehran, Iran.. It is interesting to note that although lady birds can reduce aphid infestation, aphid-tending ants reduce lady birds effectiveness to control or limit aphid populations⁸Riddick, E.W. Identification of Conditions for Successful Aphid Control by Ladybirds in Greenhouses. Insects 2017, 8, 38. https://doi.org/10.3390/insects8020038 . Biological control of any pest is not so easy. Much more research needs to be done. I guess the climatic conditions must be perfect as it has been reported that a 63.88-64.91% increase in yield was achieved using parasitoid Aphidius colemani Viereck and larvae of the predatory coccinellid. Although the cost of biocontrol was much higher than chemical control, the yield compensated for it⁹Eid, A.E., El-Heneidy, A.H., Hafez, A.A. et al. On the control of the cotton aphid, Aphis gossypii Glov. (Hemiptera: Aphididae), on cucumber in greenhouses. Egypt J Biol Pest Control 28, 64 (2018). https://doi.org/10.1186/s41938-018-0065-9. One of the best passive biological ways to control us by using Smar Glass which is an architectural cover that blocks 85% of ultraviolet (UV) light, 19% of PAR, 58% far-red, and 26% red light. It was found that lettuce released volatiles that are not favoured by Green Peach Aphids in Olfactometer Bioassay¹⁰Hamoui, Z., 2022. Effects of novel greenhouse covering materials on the physiology and quality of lettuce cultivars and their attractiveness to aphids..

Natural enemies for aphids are¹¹Sæthre M-G, Godonou I, Hofsvang T, Tepa-Yotto GT, James B. Aphids and their natural enemies in vegetable agroecosystems in Benin. International Journal of Tropical Insect Science. 2011;31(1-2):103-117. doi:10.1017/S1742758411000191:

• Aphidius matricariae
• Cheilomenes propinqua (Mulsant, 1850),
• Cheilomenes sulphurea (Chevrolat, 1837)
• Ischiodon aegyptius (Wiedemann, 1830),
• The obligate entomopathogen Neozygites sp.,
• The parasitoids Lysiphlebus testaceipes (Cresson, 1880)
• Aphelinus ficusae (Prinsloo & Neser, 1994 (South Africa))¹²https://www.waspweb.org/Chalcidoidea/Aphelinidae/Classification/
• Lysiphlebus testaceipes
• Hyperparasitoids such as Syrphophagus africanus (Gahan, 1932). (L. testaceipes, S. africanus and A. spiraecola are pecies from West Africa).

Chemical control:

It is recommended to combine your chemical program with other pests control. Recommendations must be sourced from your local chemical company, such as Syngenta¹³https://www.syngenta.co.za/contact-us-syngenta-south-africa.

References

• 1
  Jamie E. Hopkinson, Myron P. Zalucki, David A.H. Murray, Host selection and parasitism behavior of Lysiphlebus testaceipes: Role of plant, aphid species and instar, Biological Control, Volume 64, Issue 3, 2013, Pages 283-290, ISSN 1049-9644, https://doi.org/10.1016/j.biocontrol.2012.11.016
• 2
  Mary Louise Flint, Steve H. Dreistadt, Interactions among convergent lady beetle (Hippodamia convergens) releases, aphid populations, and rose cultivar, Biological Control, Volume 34, Issue 1, 2005, Pages 38-46, ISSN 1049-9644, https://doi.org/10.1016/j.biocontrol.2005.03.019.
• 3
  Russell, Edmund P. “Enemies hypothesis: a review of the effect of vegetational diversity on predatory insects and parasitoids.” Environmental entomology 18.4 (1989): 590-599.
• 4
  Sheehan, William. “Response by specialist and generalist natural enemies to agroecosystem diversification: a selective review.” Environmental Entomology 15.3 (1986): 456-461.
• 5
  Kocourek, F., Havelka, J., Beránková, J. and Jaroŝik, V. (1994), Effect of temperature on development rate and intrinsic rate of increase of Aphis gossypii reared on greenhouse cucumbers. Entomologia Experimentalis et Applicata, 71: 59-64. https://doi.org/10.1111/j.1570-7458.1994.tb01769.x
• 6
  Rabasse, J.M., van Steenis, M.J. (1999). Biological Control of Aphids. In: Albajes, R., Lodovica Gullino, M., van Lenteren, J.C., Elad, Y. (eds) Integrated Pest and Disease Management in Greenhouse Crops. Developments in Plant Pathology, vol 14. Springer, Dordrecht. https://doi.org/10.1007/0-306-47585-5_16
• 7
  Ali Asghar Talebi1, Abbas Ali Zamani1, Yaghoub Fathipour1, Valiollah Baniameri2, Katayun Kheradmand1 and Mostafa Haghani 11 Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box: 14115-336, Tehran, 2Department of Agricultural Entomology, Plant Pests & Diseases Research Institute, P. O. Box: 1454-19395, Tehran, Iran.
• 8
  Riddick, E.W. Identification of Conditions for Successful Aphid Control by Ladybirds in Greenhouses. Insects 2017, 8, 38. https://doi.org/10.3390/insects8020038
• 9
  Eid, A.E., El-Heneidy, A.H., Hafez, A.A. et al. On the control of the cotton aphid, Aphis gossypii Glov. (Hemiptera: Aphididae), on cucumber in greenhouses. Egypt J Biol Pest Control 28, 64 (2018). https://doi.org/10.1186/s41938-018-0065-9
• 10
  Hamoui, Z., 2022. Effects of novel greenhouse covering materials on the physiology and quality of lettuce cultivars and their attractiveness to aphids.
• 11
  Sæthre M-G, Godonou I, Hofsvang T, Tepa-Yotto GT, James B. Aphids and their natural enemies in vegetable agroecosystems in Benin. International Journal of Tropical Insect Science. 2011;31(1-2):103-117. doi:10.1017/S1742758411000191
• 12
  https://www.waspweb.org/Chalcidoidea/Aphelinidae/Classification/
• 13
  https://www.syngenta.co.za/contact-us-syngenta-south-africa.

References

• 1
  Jamie E. Hopkinson, Myron P. Zalucki, David A.H. Murray, Host selection and parasitism behavior of Lysiphlebus testaceipes: Role of plant, aphid species and instar, Biological Control, Volume 64, Issue 3, 2013, Pages 283-290, ISSN 1049-9644, https://doi.org/10.1016/j.biocontrol.2012.11.016
• 2
  Mary Louise Flint, Steve H. Dreistadt, Interactions among convergent lady beetle (Hippodamia convergens) releases, aphid populations, and rose cultivar, Biological Control, Volume 34, Issue 1, 2005, Pages 38-46, ISSN 1049-9644, https://doi.org/10.1016/j.biocontrol.2005.03.019.
• 3
  Russell, Edmund P. “Enemies hypothesis: a review of the effect of vegetational diversity on predatory insects and parasitoids.” Environmental entomology 18.4 (1989): 590-599.
• 4
  Sheehan, William. “Response by specialist and generalist natural enemies to agroecosystem diversification: a selective review.” Environmental Entomology 15.3 (1986): 456-461.
• 5
  Kocourek, F., Havelka, J., Beránková, J. and Jaroŝik, V. (1994), Effect of temperature on development rate and intrinsic rate of increase of Aphis gossypii reared on greenhouse cucumbers. Entomologia Experimentalis et Applicata, 71: 59-64. https://doi.org/10.1111/j.1570-7458.1994.tb01769.x
• 6
  Rabasse, J.M., van Steenis, M.J. (1999). Biological Control of Aphids. In: Albajes, R., Lodovica Gullino, M., van Lenteren, J.C., Elad, Y. (eds) Integrated Pest and Disease Management in Greenhouse Crops. Developments in Plant Pathology, vol 14. Springer, Dordrecht. https://doi.org/10.1007/0-306-47585-5_16
• 7
  Ali Asghar Talebi1, Abbas Ali Zamani1, Yaghoub Fathipour1, Valiollah Baniameri2, Katayun Kheradmand1 and Mostafa Haghani 11 Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box: 14115-336, Tehran, 2Department of Agricultural Entomology, Plant Pests & Diseases Research Institute, P. O. Box: 1454-19395, Tehran, Iran.
• 8
  Riddick, E.W. Identification of Conditions for Successful Aphid Control by Ladybirds in Greenhouses. Insects 2017, 8, 38. https://doi.org/10.3390/insects8020038
• 9
  Eid, A.E., El-Heneidy, A.H., Hafez, A.A. et al. On the control of the cotton aphid, Aphis gossypii Glov. (Hemiptera: Aphididae), on cucumber in greenhouses. Egypt J Biol Pest Control 28, 64 (2018). https://doi.org/10.1186/s41938-018-0065-9
• 10
  Hamoui, Z., 2022. Effects of novel greenhouse covering materials on the physiology and quality of lettuce cultivars and their attractiveness to aphids.
• 11
  Sæthre M-G, Godonou I, Hofsvang T, Tepa-Yotto GT, James B. Aphids and their natural enemies in vegetable agroecosystems in Benin. International Journal of Tropical Insect Science. 2011;31(1-2):103-117. doi:10.1017/S1742758411000191
• 12
  https://www.waspweb.org/Chalcidoidea/Aphelinidae/Classification/
• 13
  https://www.syngenta.co.za/contact-us-syngenta-south-africa.