Since most of the infestations generally occur below the soil level, these problems can go undetected until harvesting season arrives. pamphlet and sweet potato weevils. Taiwan Agricultural Chemicals and Toxic Substances Research Institute Council of Agriculture (TACTRI/COA). Chittenden, F. H. (Frank Hurlbut), 1858-1929. Losses of 3–80% were recorded in Indonesia, throughout several locations and seasons  and with higher damage observed during the dry season . Pillai et al. Photo 7. sweetpotato weevil, Cylas formicarius, on the outside of a storage root left on the soil. Photo 1. Sweet potato is one of the five most important crops in 40 developing countries besides rice, wheat, maize, and cassava . Mid-drought begins when food production is severely restricted by the lack of rain, and ends when there is return of good rains and further frosts cease to occur. Jun 11, 2019 / Published Date: Larvae tunnelling inside the tubers will indirectly facilitate the entry of soilborne pathogens, which can cause further damage from secondary infections by fungi and bacteria . A pheromone is available which attracts male weevils (Photo 8). Sweet potato weevil control was acceptable in a field planted away from a weevil-infested field, whereas the tubers were heavily infested when the fields were adjacent to each other. However, the effect of their release into the environment in the long term, ecosystem consequences, effects on ecological needs, and potential of resistance should be well studied before this method can be widely practised . The death of the insect host usually is a result from depletion of nutrient resources, mechanical damage, and toxicosis . Their infestation normally causes 20 to 50% of damage in most commercial plantations. To overcome this problem, crop residues in the field must be destroyed after harvest . The cuticle degradation by proteases starts with the absorption of enzyme onto the cuticle by nonspecific electrostatic bonds, followed by protease active site contact with specific peptide sequences (on the cuticle) and lastly the hydrolysis of amino acids or peptide fragments of the cuticular protein. … Mulching with elephant grass at a level between 1 and 5 tonnes per hectare decrease the infestation of weevil as well as help to improve the yield of storage root . Also, the IPM program implemented in Taiwan has helped the local farmers; these applied methods include crop rotation, alternate host removal, continuous pheromones trap and mulching . The lack of whole genome sequencing data of sweet potato has hindered DNA fingerprinting, development of molecular markers, and genetic analyses of this crop. United States Environmental Protection Agency (USEPA). Drenching of Soil at 50 and 80; 60 and 90; and 50, 65 and 80 days after planting were similarly effective in destroying the incidence and intensity of weevil damage . Palaniswami and Mohandas  conducted a study in India to investigate the efficiency of reridging in sweet potato plant in reducing the infestation of weevils.  conducted a study to transform Cry3A gene into sweet potato roots to fend against sweet potato weevil, Cylas formicarius. Figure 1: Weevil feeding damage on root, stem, vine and leaves of sweet potato. "Immense losses of sweet potatoes in the Gulf States are being caused by the sweet-potato weevil. Biocontrol agents are generally divided into three main groups: Group 1—agents will recycle naturally to exert permanent effect of pest control once they are introduced into the pest population; Group 2—agents disappear quickly from the pest population and they must be reapplied regularly; and Group 3—agents can behave like Group 1 or Group 2 based on the combination of pest species, environment, and agent strains. Dig up a storage root and look for damage to the skin, and feeding tunnels of the larvae inside. Government Printing Office. Read more here! The impact on yield depends to a great extent on the soil and weather. The selection of different cultivars over the years by the farmer was based on a higher resistance to weevils, for instance, the use of deeprooted cultivars can make the roots less accessible for oviposition female weevils [37,85,86]. It is shiny and smooth, but when you look closely, you will notice that they grow short hairs. However, grubs cause most damage by tunnelling through the stems (Photos 1-3) and storage roots (Photo 4). Watch out for the following symptoms, which can be indicative of the presence and infestation of sweet potato weevil: In case of severe infestation, it can lead to up to 100% of losses of host crop, making it a serious concern amongst many commercial growers. As the larvae feed, the sweet potato will impart a bitter flavour and terpene odour, making it unsuitable for the consumption of human or livestock. There was a drastic decrease in Cylas formicarius species in India where the sweet potato was intercropped with cowpea, taro or rice . But occurrence differs in different locations depending on the type of cultivar used and management methods adopted. Biological control method using entomopathogenic nematodes has been found to have beneficial interaction with sweet potato and offers a promising way to suppress sweet potato weevil population. O. Setokuchi, T. Sugimoto, T. Yamaguchi et al., “Efficiency of the sterile insect release method as an eradication measure for the sweet potato weevil, L. Alphey, M. Benedict, R. Bellini et al., “Sterile-insect methods for control of mosquito-borne diseases: an analysis,”. Round and oval shape tubers of sweet potato were also infested by weevil more severely as compared to longer ones. All results obtained in various years indicated that the SIR technique is a beneficial method in preventing infestation of weevil . A. Gatehouse, “A fusion protein containing a lepidopteran-specific toxin from the South Indian red scorpion (, H. M. M. Ibrahim, N. W. Alkharouf, S. L. F. Meyer et al., “Post-transcriptional gene silencing of root-knot nematode in transformed soybean roots,”, J. F. Kreuze, I. S. Klein, M. U. Lazaro et al., “RNA silencing-mediated resistance to a crinivirus (Closteroviridae) in cultivated sweetpotato (. crediting UNT Libraries Government Documents Department.