## 3 Results
### EOs Rich in Alpha-Phellandrene and Their Main Biological Activities
#### 3.4.3 Biopesticides and Repellent Activity  
The use of natural pesticides based on EOs represents an increasingly suitable method for crop protection and, in this way, EOs rich in alpha-phellandrene have shown promising results. [PERSON] et al. [92] determined the fumigant toxicity of the EO from _Boswellia carterii_(alpha-phellandrene 6.8%) against legume beetles. They found that 0.096 \(\upmu\)L of the EO per ml of air was effective against _Callusbruchus chinensis_ after 24 h of treatment, obtaining more than 90% mortality. _B. carterii_ EO was, likewise, effective against _C. maculatus_, as the LC\({}_{90}\) of individuals was even lower (0.075 \(\upmu\)L/mL air). Alpha-phellandrene was found to be the main component (28.5%) of the EO obtained from _S. areira_ leaves and displayed the lowest concentration to cause the mortality of half of the _Metopolobium dirhatum_ nymphs tested, a well-known cereal crop pest, when compared to others EOs. Furthermore, the exact LC\({}_{50}\) for winged adults was 7.5 mg/mL at 24 h after contact exposure [93]. A recent study by [PERSON] et al. [94] described the potential of dill (_A. gravelens_) seed EO, containing 13.1% alpha-phellandrene, in controlling the spread of gypy moths (_Lymuntria dispur_). [PERSON] et al. found that dill seed EO was the most effective, compared with other Eos, when introduced as 1% of the larvae diet, resulting in a reduction of 78% of larval molting at a concentration of 0.5%. The EO obtained from _Curcuma longa_ leaves, with an alpha-phellandrene concentration of 42%, showed an LC\({}_{90}\) for _Lucilia cuprina_ larvae at 1.5 \(\upmu\)L/cm\({}^{2}\) after 6h exposure [95]. [PERSON] et al. [96] formulated a nanoemulsion of dill EO, with an alpha-phellandrene concentration of 20.8%, obtaining an LC\({}_{90}\) of 65.0 ppm against thirrd and fourth instar larvae of _A. stephensi_. Another study, [97], proved the effectiveness of using an EO made from the seeds of _Nigella sativa_ (alpha-phellandrene 14.9%), against the same organism, obtaining an LC\({}_{90}\) of 172.6 ppm after 24 h exposure. [PERSON] et al. also studied the same effect against _Ae. aegypti_ (LC\({}_{90}\) = 300.8 ppm) and _Culex quinquefascitus_ (LC\({}_{90}\) = 364.0 ppm). Likewise, [PERSON] et al. [98] focused on the larvicidal effect against the Culicidae family, specifically in the inhibition of the acetylcholine esterase of the Asian tiger mosquito (_Ae. albopictus_). This group found that dill EO with alpha-phellandrene as the main component, had strong larvicidal activity (>90% mortality) at a concentration of 0.1 mg/mL. To prevent _Ae. aegypti_ from oviposition, [PERSON] et al. [99] used the EO from _Comniophora leptophoeos_ leaves, with 26.3% of alpha-phellandrene, and found strong oviposition deterrent effects in a concentration between 25.0 and 100.0 ppm. Their bioassays also showed good larvicidal activity with an LC\({}_{50}\) of 99.4 ppm. Against the larvae of mosquitos, the EO from the leaves of _Echinophora lamodiana_ (alpha-phellandrene 14.1%) showed an LC\({}_{90}\) of 169.1 and 46.0 ppm against _A. aegypti_ and _A. quadrinculatus_, respectively. Furthermore, [PERSON] et al. [100] studied the larvicidal effects of the EO from _Piper klotzschianum_ seeds with a concentration of alpha-phellandrene of 17% against _Ae. aegypti_. It was found that 13.3 \(\upmu\)L/mL was able to kill 50% of individuals after 48h incubation with the EO. This group also studied the lethality against _Artemia salina_, which is usually known as 'the brine shrimp lethality assay', where the LC\({}_{50}\) was 14.0 \(\upmu\)L/mL. Alpha-phellandrene has also been tested as a repellent against various organisms. For instance, the ethyl acetate extracts from _Myrica sale_ inflorescences (alpha-phellandrene 25%) repelled 82.1% of mosquitos (_Ae. aegypti_) tested in a study lead by [PERSON] et al. [101]. [PERSON] et al.