Clemson University's Regulatory and Public Service Program listed "diseases vectored by insects" among bioterrorism scenarios considered "most likely". Because invasive species are already a problem worldwide one University of Nebraska entomologist considered it likely that the source of any sudden appearance of a new agricultural pest would be difficult, if not impossible, to determine. Lockwood considers insects a more effective means of transmitting biological agents for acts of bioterrorism than the actual agents. Insect vectors are easily gathered and their eggs easily transportable without detection. Isolating and delivering biological agents, on the other hand, is extremely challenging and hazardous. In one of the few suspected acts of entomological bioterrorism an eco-terror group known as The Breeders claimed to have released Mediterranean fruit flies (medflies) amidst an ongoing California infestation. Lockwood asserts that there is some evidence the group played a role in the event. The pest attacks a variety of crops and the state of California responded with a large-scale pesticide spraying program. At least one source asserted that there is no doubt that an outside hand played a role in the dense 1989 infestation. The group stated in a letter to then Los Angeles Mayor Tom Bradley that their goals were twofold. They sought to cause the medfly infestation to grow out of control which, in turn, would render the ongoing malathion spraying program financially infeasible. The Biological and Toxic Weapons Convention (BWC) of 1972 does not specifically mention insect vectors in its text. The language of the treaty, however, does cover vectors. Article I bans "Weapons, equipment or means of delivery designed to use such agents or toxins for hostile purposes or in armed conflict." It would appear, due to the text of the BWC, that insect vectors as an aspect of entomological warfare are covered and outlawed by the Convention. The issue is less clear when warfare with uninfected insects against crops is considered. It has been suggested that insects could get genetically engineered via technologies such as CRISPR to create GMO "killer mosquitoes" that cause plagues that wipe out staple crops. This potential has been indicated in the use of genetically modified mosquitoes to curb the spread of diseases related to mosquitoes, such as Zika, and the West Nile virus using mosquitoes modified using CRISPR to no longer carry the pathogen, which shows the capability to implant diseases or pathogens via genetic modification is potentially present. It has been suggested by the Max Planck Institute for Evolutionary Biology that current US research into genetically modified insects for crop protection via infectious diseases which spread genetic modifications to crops on mass could lead to the creation of genetically modified insects for use in warfare.