NoLo Bait is a grasshopper suppression bait made from flaky wheat bran which is sprayed with a suspension of distilled water, a sticking agent, and Nosema locustae spores. It is non-toxic to humans, livestock, wild animals, birds, fish, or life forms other than grasshoppers and species of insects closely related to grasshoppers. USDA has set a standard that 8 or more grasshoppers per square yard can be considered economically damaging. In many cases, to the casual observer, grasshoppers do not seem to be a noticeable problem until infestations reach 40 or more per square yard. That is when they become noticeably apparent and by that time you want "belly-up overnight" control. However, it is very important to understand that NoLo Bait or "Nosema locustae" does not work rapidly. It is a subtle disease that is naturally occurring and takes time to develop to levels that can be readily identified. By putting out the bait at the minimum label rate of 1 lb. per acre equivalent, you are performing what is called an "inoculative" release. This will begin the disease process in the population present at that time; however, depending on the grasshopper population densities and varying age groups at the time, the level of inoculation will vary.
For instance, if you have more than 8 grasshoppers per sq. yard and put out one pound to the acre one time, you will probably have serious competition for each flake of bran out there. Quite possibly there will be a large percentage of grasshoppers that don't even get one flake to themselves. In that case, there will be many that will not become infected, at least until they begin consuming those around them that have become sick enough to become attractive as a food source to the healthy grasshoppers, thereby spreading the disease. Because grasshoppers are extremely migratory and can move over great distances, it is optimal to inoculate your area frequently throughout the season. This will help to spread the infection further and aid in long term control. Nosema may not work as quickly as chemical pesticides, but used correctly, it will have a noticeable impact on populations in the long term.
Due to the nature of the disease, the effects will vary according to age and species of the grasshopper and the amount of spores that grasshopper was able to consume. In very young, newly hatched grasshoppers, death may occur within a week. Unfortunately, if you are not planning follow up treatments, this may not really be the optimal time to infect, simply because it does not offer long term carryover. The young grasshoppers die quickly and dry up and disappear. Healthy grasshoppers migrate in, and you can't tell what happened. By the time grasshoppers reach the third stage of growth (3rd instar) they have developed enough body mass to allow the spores to reproduce to some extent. The infected grasshoppers will become lethargic and dramatically slow or quit feeding, but will not die immediately. This stage allows for some spreading of the disease to take place as healthy grasshoppers come in and cannibalize them. Once grasshoppers are almost to adulthood, infection results in the loss of appetite, lethargy, increased spore production inside their bodies and therefore more spread of the disease. It is actually good to see them very slowly moving about and yet not feeding because it is only in these lethargic but living grasshoppers that the disease can continue to propagate and eventually spread to more of the population. "Belly up" will not necessarily offer the long term control this disease is so capable of producing. In young adults, reproduction and egg laying may be severely depleted or even stopped. When reproduction does take place, quite often the spores will be passed on in the sticky substance that surrounds the egg pods and the young will become infected as they chew their way out of the egg pod and crawl up through the soil to the surface after hatching. In this case they will probably not survive their first molt.
This process explains why you may observe more obvious results the season after application has taken place than during the season in which you inoculated. This is due to an overall decrease in egg laying capability, and infection of the new spring hatch. Follow-up applications each year grasshopper populations are on the increase are useful to continue this process. Winter and spring weather will also have an effect on the spring hatch, as will the cycle the population is in at the time. grasshopper cycles peak and valley approximately every 7 years. This can vary by one to two years either way, but basically, every 7 years or so, they will reach an all time high or an all time low. It is helpful to check with the Dept. of Agriculture in your state to find out what the population predictions are for your area on a year-by-year basis. You can then plan your releases accordingly. If populations are in the uphill trend, it is definitely advisable to begin the disease process immediately and to continue to inoculate each year until the peak has happened and the downward cycle becomes evident. If you get started soon enough and a large enough percentage' of grasshoppers are inoculated, you may deter severely escalating populations from ever actually taking place. The more area treated on a consistent basis, the more long term control you can expect to take place. Optimally, spreading bait frequently throughout the season will be more advantageous than just once at the label minimum application rate.
Nosema locustae spores are single celled animals otherwise known as protozoans. The spores that are sprayed on the bran are in the "resting" or protected" stage of the protozoan's life cycle. By "resting" or "protected", we mean that they have reached a stage of their life cycle when they automatically form a protective layer around the cell that neither takes in or lets out anything, from water to waste. It is in this stage that they wait to be ingested by a grasshopper. The spore stage can persist in the soil for years. Once the spores are ingested by the grasshopper, they become activated in the grasshopper's mid-gut. The spores "germinate" or extrude a filament from the cell wall. In the process of extruding this filament, the spores pierce the mid gut wall of the grasshopper and in very young 1st instar (growth stage) grasshoppers, death usually occurs very quickly due to septicimia (bacteria invading the grasshopper and causing death). The spores then continue to reproduce, attacking the fat body in the grasshopper. It is this action that causes infected grasshoppers to become lethargic and reduce their feeding and reproduction ability. In essence, when a grasshopper consumes the spores, it is like giving them a fatal case of the flu or giardia. The disease takes time to develop.
Some of the symptoms of the disease will occur more quickly than others. The severity of the symptoms is dependent upon the age and species of the grasshopper at the time of treatment, the amount of spores consumed, and the overall health and vigor of the grasshopper at the time it becomes infected. Symptoms of infection may be observed in the field in the following manner: Infected grasshoppers will become more lethargic than usual. When they are disturbed they will typically hop and, upon landing, fall to one side or the other. Their equilibrium has been effected. After falling to one side or the other, they typically crawl unsteadily a little way before hopping again. Often they will not hop again unless forced to. They also typically crawl up a grass stalk or seek someplace to "roost" or cling to. It is often in this position that dying infected grasshoppers will remain and evidence of cannibalism will be apparent.
Healthy grasshoppers will feed on infected grasshoppers from the abdomen up to the thorax (mid section) which is just behind the front legs. They don't usually eat the head or the hard "plate-like" shield behind the head which covers the thorax. Visual examination of a grasshopper for evidence of infection can be done by holding live grasshoppers just behind the head along the hard plate. Turn the grasshopper over and look at the underside of the abdomen. On each side of the abdomen there are two depressions which run the length of the abdomen beside the segments in the sides. In many species of healthy grasshoppers, the depressions will be a darker color than the rest of the abdomen, or even look like lines running the length of the abdomen. When a grasshopper becomes infected with nosema, often these lines will disappear and the entire abdomen will become a "creamy" whitish or greyish color. This can be an indicator that spore reproduction is heavy. Often, in a heavily infected individual, the eyes will also lose their dark color and become whitish or hazy looking. If the head turns white it is amazing if the grasshopper is still alive.
Infection with Nosema can make death to grasshoppers already carrying other commonly associated diseases occur more quickly. An example of this is seen in an associated disease called Malamoeba Locustae . Malamoeba Locustae occurs commonly in most grasshopper populations. Like Nosema, it is not usually present in large enough numbers to cause death. Once the grasshopper ingests Nosema, however, Malamoeba levels often soar - triggered by the Nosema infection. Both organisms compete for the fat body to reproduce. The cause of death, when Malamoeba is present at the same time as Nosema, can be ascertained by a dark brownish-black coloration of the abdomen and dark body fluid seeping out. The abdomen will hang limp and readily fall apart.