Bacillus Thuringiensis var. San Diego

 

            Bacillus Thuringiensis is a bacteria that when ingested will kill potato beetles and other insects that feed of the leaves of plants. When the bacteria reaches the stomach of the insects it will start to cause holes in the lining of their intestines which causes the Potato Beetles to stop feeding after a few hours and die after two or three days.  The holes in the insects stomach is caused by a protein produced when resources are limited called Cry endotoxins. When the Cry endotoxins enter the insects intestines they bind to protein receptors called cadherin on the membrane of the gut. This causes a chain reaction as shown in the figure 1 bellow that results in the buildup of toxins and the ultimate demise of the Potato beetle. (Jurat-Fuentes, 2015) 

Figure 1: effects of Bacillus Thuringiensis on an insect

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bacillus Thuringiensis is applied using a spray over the leaves of plants. The best time for application would be in mid spring when the potato beetle is first emerging form the soil since it needs to be ingested to kill insects. There are certain alkaline metals that could harm Bacillus Thuringiensis and decrease effectiveness that can be found in some waters. To ensure the bacteria works the best it can water should be tested. If high levels of alkaline metals are found citric acid should be added to the water in order to neutralize the effects of the alkaline metals.