Source: Kansas State University's myFields Sugarcane Aphid Tracker.
Below are seven videos that are part of our sugarcane aphid management series. In the videos, agronomist Brent Bean, Ph.D., summarizes the research findings into best management practices and next steps for growers.
Sugarcane Aphid Biology
Tolerant vs. Susceptible Hybrids
When to Apply Insecticide
Insecticide Rates and Application
Control With Other Pests
Late Season Control
Integrated Pest Management and Best Management Practices
Texas A&M AgriLife Extension Video Resources:
SCA Identification and Estimating SCA Numbers
The Sorghum Checkoff recently released the Defense Against the Sugarcane Aphid booklet in order to provide more information to growers. The goal of the document is to assist growers in effectively managing the pest to avoid yield and revenue loss. The 20-page document covers topics from identifying the pest and aphid effects to scouting and when to treat.
Downloadable PDF >>
The sugarcane aphid, Melanaphis sacchari, was discovered late in the 2013 growing season in the coastal sorghum regions. The sugarcane aphid is a new pest to the U.S. sorghum industry, and it is capable of causing substantial damage to the crop if left unmanaged. It is important for producers to be proactive and constantly scout for and monitor the pest because early detection is critical to minimize the aphid’s harmful effects.
Sugarcane aphids will only survive and multiply significantly in sorghum genotypes, including Johnsongrass, shattercane, sorghum-sudangrass, sudangrass, forage sorghum and grain sorghum. Sugarcane aphids will not survive on any of the major crops such as corn, cotton, soybeans or wheat. However, sugarcane aphids are distributed by the wind, so small colonies can be found in these crops, but at this time, they have not been found to be of economic importance.
Heavy infestations of the sugarcane aphid cause leaves to be covered with a sticky, shiny substance called honeydew. This honeydew is made up of plant sugars and water, which are harmless to animals. Honeydew is water soluble and washes off of the plant by rain or sprinkler irrigation. If honeydew is left on the plant, it eventually dries into a harmless residue.
Black sooty mold will often begin growing on the honeydew of sorghum leaves. This black sooty mold blocks out sunlight and decreases the plant’s ability to produce sugars through photosynthesis. Over time, black sooty mold causes leaves to turn yellow and eventually the leaf tissue dies.
Loss of plant sap from the sugarcane aphid feeding on sorghum leaves takes away nutrients from the plant that could otherwise be utilized for plant health and grain yield. Plant stress caused by the sugarcane aphids can also lead to uneven and lack of head emergence, poor grain set and will likely contribute to an increase in lodging.
Source: Texas A&M AgriLife Extension
Threshold levels change and vary between regions. It is important to check with local experts to determine regional thresholds and scouting procedures. A simple rule of thumb is to treat when 25 percent of the plants are infested with 50 aphids per leaf.
in South and Central Texas, entomologists recommend a threshold of 50-125 sugarcane aphids per leaf. However, the Texas High Plains entomologist recommendations are based more on percent plants infested with sugarcane aphids. Threshold can range from 20-30 percent of the plants infested depending on sorghum growth stage.
See the links below for information on scouting and when to treat sugarcane aphids in Texas and Kansas:
Other Management Resources:
Sivanto Prime and Transform WG prove to be the most effective labeled products. Sivanto Prime, flupyradifurone, is sold by Bayer CropScience under a federal 2ee label for use on grain sorghum. There is currently a 2018 section 18 label on Transform for use in Alabama, Arizona, Arkansas, Colorado, Georgia, Illinois, Kansas, Louisiana, Mississippi, Missouri, New Mexico, North Carolina, Oklahoma, Texas and Virginia. Labels can also be requested through local Dow AgroSciences representatives or herbicide distributors.
One of the benefits of Transform and Sivanto Prime is they are not harmful to beneficial insects, which is important for the control of sugarcane aphids. Care should be taken in adding other insecticides to the mix that could be harmful to beneficial insects. Additionally, movement of Sivanto Prime and Transform in the plant is minimal, making coverage essential for adequate control.
When other insects such as headworms and midge are present at threshold levels it is tempting to use one of the cheaper pyrethroids to control these insects. However, if sugarcane aphids are present in the field the use of pyrethroids may cause the aphids to quickly multiply due to the reduction in the beneficial population. Under these conditions consider using Prevathon, Blackhawk or other appropriate insecticides that maintain the beneficial insect population critical for keeping sugarcane aphid numbers in check.
When applying insecticides, it is important to read the full product label and follow instructions carefully. In general, ground rig application tends to work better than air application. Insecticide coverage is critical for sugarcane aphid control. Use spray nozzles and a spray pressure that maximizes coverage. Increasing the volume of water above the minimum requirements listed on the insecticide labels is recommended. Control will be lessened if insecticide application is made under cool conditions, including temperatures into the low 60 degrees Fahrenheit. The duration of control will depend on many factors, but under heavy infestation levels, expect anywhere from 5-14 days with 10 days being the most common length of control. Check with local experts on the use of adjuvants. Research on their effectiveness has been mixed.
Over the last three years, the United Sorghum Checkoff Program has provided a list of hybrids known to have at least some tolerance to the sugarcane aphid. This list was comprised of only hybrids where tolerance had been observed by third parties. Going forward, the Sorghum Checkoff will no longer be providing this list. Seed companies have now had multiple growing seasons to observe their hybrids and should have a good grasp of their tolerance level. Growers in those regions where sugarcane aphid has been a reoccurring issue should visit with their seed company representative as well as seek advice from regional extension agronomists and entomologists on choosing hybrids.
When choosing a sugarcane aphid tolerant hybrid, all of the criteria used for selecting a non-tolerant hybrid should be considered. Growers are better off to plant a regionally adapted non-tolerant hybrid with good yield potential over a poorly adapted tolerant hybrid. Sugarcane aphid can be controlled with good scouting and timely insecticide application, if needed.
Current commercially available tolerant hybrids are NOT immune from sugarcane aphid. However, research has consistently shown that sugarcane aphid reproduce slower on tolerant hybrids and in some cases are able to withstand a higher sugarcane aphid population without a reduction in yield compared to susceptible hybrids. Tolerant hybrids should be scouted and an insecticide should be applied once the economic threshold has been reached.
Private companies and university sorghum breeders continue investigating resistance. They have identified better sources of sugarcane aphid resistance and tolerance and are working to incorporate these qualities into commercially available hybrids.
Biological control along with tolerant hybrids is the key to long term management of sugarcane aphid in sorghum. Below are a set of videos by Kansas State University discussing key predators and how they interact with host plant resistance to control sugarcane aphids.
Host Plant Resistance and Biological Control
To protect sorghum from potential early season infestations, growers should consider planting seeds treated with an insecticide seed treatment. Acceptable seed treatments include Cruiser (thiamethoxam), Poncho and Nipsit (clothianidin) and Gaucho (imidaclorprid), which should give up to 40 days of sugarcane aphid control.
If sugarcane aphids are in significant numbers in the sorghum head or on the upper leaves, harvesting can be impeded due to honeydew. There is not a good threshold level at this time for when to spray sugarcane aphids to assist in harvest.
If sugarcane aphids are present and produce a significant amount of honeydew that can gum up the combine, many producers are opting to spray an insecticide to eliminate the risk of harvesting issues. Either Transform or Sivanto Prime may be used prior to harvest. The pre-harvest interval is 14 days for Transform in all states. The pre-harvest interval for Sivanto Prime is also 14 days in Texas, Kansas, Oklahoma, Arkansas and Nebraska on a Section 24c label. In states without a Section 24c label the pre-harvest restriction is 21 days. Since sugarcane aphids only need to be controlled for a short period of time in order to get through harvest, the lowest effective insecticide rate should be used. Both products can be mixed with harvest aid desiccants if desired. Research has shown the use of desiccants alone can temporally cause sugarcane aphids to migrate into the heads and away from the desiccated leaves making harvest more difficult.