## 6 Genetics and Biotechnology in the Service of IPM
Even so, there are some genetically modified beneficial organisms that have been developed or tested for biological control. A strain of the entomopathogenic fungus _Beaureria bassiana_has been modified to increase its virulence and stability against diverse insects [266; 267; 268; 269]. A transgenic strain of the entomopathogenic bacterium _Bacillus thuringiensis_ that produces a scorpion toxin that is highly specific and lethal to the cotton bollworm has also been tested [267; 270; 271]. These are just two examples of the latest benefits in the area, of which there are many others [272]. The insect pests themselves may also be susceptible to genetic modification. The sterile insect technique (SIT) is a pest control method where large numbers of sterile insects are released into a target population to suppress reproduction [273]. In this respect, genetics and biotechnology can improve the mass rearing and sterilization processes, making SIT more efficient and cost-effective. The four main strategic options in using the SIT--suppression, containment, prevention, and eradication--with examples of each option are described in detail in the study by [PERSON], [PERSON], and [PERSON] [274]. Another approach that involves genetic engineering and pests is the use of RNA interference (RNAi). RNAi is a method that silences specific genes in pests by delivering double-stranded RNA molecules that trigger a natural mechanism of gene regulation [275]. RNAi technology can be used to silence specific genes in pests, causing them to become less viable or develop abnormally [276]. Gene drives consist of genetic elements that are efficiently transmitted among sexually reproducing individuals. They inherit genetic traits that are passed to future generations with a higher probability than with Mendelian inheritance, even if these elements reduce the fitness of such individuals. Therefore, this is a method that involves spreading a desired genetic trait through a population quickly [277]. There are several approaches to achieving this goal, all with advantages and disadvantages [278; 279; 280], but despite all their potentials, these products are unlikely to have an easy route to market. The applicability of these strategies to new target pests, their efficacy in the natural environment, and their potential safety and acceptability as control methods are surrounded by considerable controversy and uncertainty. International agreements before the release of approved insect strains are necessary [281]. Some of these measures are well established. They have been used for years or decades to control some of the pests that plague olive groves. For example, the use of _B. thuringiensis_ has been researched and used for the control of major olive pests for at least 30 years [282]. Indeed, it is currently included in the community list of active substances approved for use in olive groves in EU countries such as Spain. There are different substances derived from 11 species of _Bacillus_ that were approved for use as fungicides, insecticides, and/or bactericides. Specifically, there are eight strains of three subspecies of _B. thuringiensis_ that were approved as insecticides [10]. Particularly in olive grove IPM, biotechnology and genetic engineering also play important roles. Although genetic modifications to the tree itself may take time to prove to be effective due to the nature of the plant, several genetic markers have been tested to obtain modifications against, for example, drought or salinity stress [282; 283; 284]. Several genetic and serological tests for the specific detection have been developed for main olive pathogens, highlighting those for _X. fastidiosa_[285; 286] that produce vascular infection and may have an asymptomatic infection phase. But it is the genetic modification of the olive pests themselves that is without a doubt the most studied and the most widely used method. As mentioned above, SIT is being used to control important pests, including olive pests [287; 288; 289].