Jaco Marais Product Manager
Potatoes are cultivated across South Africa and are considered a major crop in the vegetable production basket.
Phthorimaea operculella (Zeller 1873) (Lepidoptera: Gelechiidae), also known as the potato tuber moth (PTM) in South Africa, is an oligophagous pest insect with a preference towards solanaceous crops, including potatoes, tomatoes, and tobacco.(1,3) Originating from South America, it has been present in South Africa for more than a century and is mainly found in warm temperate and tropical regions.(2,3)
Its survival does not bode well in extremely low temperatures.(2) Therefore, the risk of introduction in such areas is usually low. Climate change may increase the abundance and activity of PTM due to drier and warmer climate conditions expected.(2)
Since both quantity and quality of tubers are important when considering potato yield, infestation of PTM can result in severe crop loss. Larvae mining into leaves does not usually translate into yield loss. However, severe infestations early in the season can cause significant damage to younger, smaller plants.(3)
As foliage decreases towards the end of the season, larvae start searching for new sources of feeding material. High risk to potatoes then occurs when larvae penetrate small cracks in the soil surface, reaching tubers and tunnelling beneath the skin.(3)
Stored tubers may also be damaged if infested tubers or egg-laying moths gain access to storage facilities.(1,3)
As with any pest, the use of an Integrated Pest Management (IPM) strategy is recommended for managing PTM populations in an environmentally and economically sound manner. This includes the following:
- Monitoring and scouting for pest
- Chemical control measures. Management of PTM resistance development to chemical Modes of Action (MoA) is critical in ensuring the sustainable use of insecticides.
- Biological control
- Cultural control
- Where applicable, use of resistant or tolerant
SumiPleo® is the perfect choice for controlling PTM as part of an IPM strategy and resistance management approach. It contains the novel active ingredient, Pyridalyl (IRAC group: UN) which was identified and developed as an insecticide by Sumitomo Chemical in Japan.
Figure 1: The chemical structure of Pyridalyl.
Key characteristics of SumiPleo® include:(4)
- Unique chemical molecule (dichloropropene derivitive) with no risk towards cross-resistance with any other molecule on the market.
- Contact action related to intestinal MoA (cell growth inhibiting effect in larvae).
- Larvae immediately cease to feed upon ingestion of SumiPleo®.
- SumiPleo® is effective against larval
- SumiPleo® has a significantly low impact against non-target and beneficial organisms like predatory mites, wasps, beetles, earthworms, and pollinators including bees.
- SumiPleo® has a short pre-harvest interval of 14
- SumiPleo® is not dependent on environmental temperature as is the case with some chemical molecules (i.e., pyrethroids).
- A formulation of the utmost quality leads to excellent rain-fastness properties as soon as the deposit has dried after application.
As part of a strategy to control PTM and reduce risk towards resistance development in a spray programme, apply at 200 ml/ha as a full cover application in 500 – 1 000 L of water as soon as the pest is noticed. Potatoes should be ridged at least twice during the cropping season to assist in the control of PTM. Note that when applying SumiPleo® against PTM, a 50% to 80% reduction in damage from Liriomyza spp. if present may be expected.
Philagro SA offers exclusive access to SumiPleo®, the latest in insecticide technology from Japan. For more information, feel free to contact your nearest Philagro representative or the product manager, Jaco Marais (072 390 3547).
References:
- CABI DIGITAL LIBRARY. Datasheet: Phthorimaea operculella (Potato tuber moth). CABI Compendium. https://www.cabidigitallibrary.org/ Date of access: 21 June 2023.
- KROSCHEL, J, SPORLEDER, and CARHAUPOMA, P. Pest distribution and risk atlas for Africa – Potato tuber moth, Phthorimaea operculella (Zeller 1873). International Potato Centre. https://cipotato.org/ Date of access: 26 June 2023.
- VISSER, D. 2011. A complete guide to vegetable pests in South Africa. Agricultural Research Council, Roodeplaat Vegetable and Ornamental Plant Institute, Pretoria. 316 pp.
- SAKAMOTO, , UEDA, N., UMEDA, K., MATSOU, S., HAGA, T., FUJUSAWA, T. and TOMIGAHARA, Y. 2005.
Research and development of a novel insecticide “Pyridalyl”. Sumitomo Kagaku 2005-I.
CONSULT THE PRODUCT LABEL FOR COMPLETE USE RECOMMENDATIONS AND LIMITATIONS
SumiPleo® is a registered trademark of Sumitomo Chemical Company, Japan. (Reg. no. L8377, Act no. 36 of 1947), contains Pyridalyl dichloropropene derivitive, danger. Philagro South Africa. PostNet Suite #378, Private bag X025, Lynnwood Ridge 0040. Pretoria: 012 348 8808 l Somerset West: 021 851 4163.
