A look at the smallest danger posed to California
California is home to a wide berth of insects, more so than most other states. Through evolution and the natural spread of insects, the number of species alone in California has greatly increased over the years, to an estimated 27,000 species, according to a University of California study. Considering around 30% of all insect species found in North America are found in California, it's no wonder why there always seems to be something underfoot. As California is such a popular travel destination, some of this biodiversity is due to invasive insects.
While most invasive insects serve no immense danger to any person on an individual scale, they can still be quite annoying or at times devastating. Based on a University of California Riverside study, there are currently around 1,686 invasive species currently crawling and buzzing around the state. Most simply pose a threat to ecosystems and farming, with insects that are mildly dangerous to individual people few and far between. Only around 20% of these invasive species are considered actual pests, though, as some can find a niche in their environments.
The Bagrada Bug is a small, harmless shield bug, less than an inch in length. Completely uninteresting on paper, couldn't even bite you. The real damage comes from the devastation to crop populations. The Brassicaceae family is the most vulnerable to it, the family consisting of vegetables such as turnips, radishes, kale, cabbage, mustard, and broccoli. Even some not beloved vegetables, such as... cauliflower. While not in their main diet, they've also been recorded snacking on legumes, corn, potatoes, and cotton. In hordes, they pose a great threat to agriculture. As of now, there are no insect species that prey on adult Bagrada Bugs. The only ways to keep them in check at the moment are insecticides, and some cultural control methods such as sanitizing soil or solarizing it, a process that involves using energy from the sun to artificially create high temperatures. The only natural reductions in the Bagrada Bug population are two lone ant species that eat the eggs laid in the soil, along with a non-insect invertebrate, a springtail. They serve as a major threat, despite their appearance.
The aptly named Red Bugs, or inaptly named Genus Pyrrhocoridae, are a group of mildly uninteresting invasive bugs. Fun taxonomical fact, bugs and insects are not the same terms. Insects refer to any arthropod with 6 legs and usually wings. Bugs, however, is a term reserved for insects with a sort of needle-like mouth, a proboscis, that pierce and suck prey or plants dry. Taxonomical tangent aside, there are roughly 300 species in the family of Red Bugs. They can't even sting or bite, really. Their main inconvenience comes in the way of large migrations, which due to their abundance in numbers, is enough to get them labeled as a pest. In some ways, Red Bugs are even beneficial, albeit in an ironic way. They feed on weeds and plants primarily and rid gardeners of one of the most prominent invasive threats, Japanese Knotweed. The weed is unharmful to humans but is known for its explosive (and invasive) growth speed, along with being very damaging to plants. On the other hand, they've also got a taste for Mallow, another invasive plant. However, Mallow plants are neither invasive nor a weed. They even offer quite substantial medical benefits, mainly relieving throat and mouth irritation. In most cases, Red Bugs are considered a very negligible threat.
The European Pepper Moth is quite a cute invasive insect all things considered. Moths typically aren't pests or viewed as such. But, due to their liking towards some edible and ornamental crops, they're on the environmentalist hit list. Regulating, or even finding their populations of young larvae and eggs is quite a challenge until it's too late. An individual can lay as many as 200 eggs, in one clump or in a dispersed manner. The caterpillars pupate under leaves or on the edges of pots, making them quite difficult to spot, given that they're just a bit over half an inch in length. Their main environmental threat comes in the form of their snacking habits. Being scavengers, they feed on almost anything available, mostly leaves. They're known to cause leaf necrosis, or the rot of certain spots that they chew on, which can severely damage plants. Their habits can also cause stem girdling, where they chew through enough of the stem to cut off the roots from the leaves, which usually proves quite worrisome for most crops. The European Pepper Moth, funnily enough, does pose quite a threat to pepper cultivation, and strawberries in California. The more inconvenient and less dangerous threat comes to popular flowers, such as roses, begonias, poinsettias, and some daisies.