of soil and waterways, and even increased risk of extinction for Colombian bird and plant species. Aside from these specific issues, there are also others raised about the costs of fumigation and if it is using too much money. This intensive program to eradicate crops with aerial spraying is the backbone of the bilateral anti-drug partnership between Colombia and United States. Proposed use of mycoherbicides In 1999, the U.S. Congress added a provision to its Plan Colombia aid package that called for the employment of mycoherbicides against coca and opium crops. The potential use of Fusarium oxysporum as part of these efforts was questioned and opposed by environmentalists. Colombia rejected the proposal and the Clinton administration waived the provision in light of continued criticism. Military programs Compared to the counternarcotics measures, the military campaign waged against the FARC and other paramilitaries appears to have achieved more success. Military aid packages that were both part of, and separate from, Plan Colombia have successfully driven the FARC out of most of their former territory and targeted the leaders of the insurgency, killing over two dozen of them. The U.S. has largely remained in a non-combatant role, providing real time intelligence, training, and military equipment. As the Colombian military (with U.S. support) continues to crack down on the FARC during the mid-2000s, the insurgency was sapped of much of their military might. Traditionally, the FARC has operated with a centralized, hierarchical command structure and a governing body called the Secretariat. With the deaths in 2008 of main leader Manuel Marulanda and second-in-command Raúl Reyes, followed by the killing of top tacticians Mono Jojoy and Alfonso Cano in 2010 and 2011, the group became increasingly disjointed. In 2001, for example, the FARC had over 18,000 fighters, but that figure fell to under 7,000 by 2014 mainly as a result of fighters abandoning the cause. In terms of land, the FARC once controlled a DMZ the size of Switzerland in 1999 and had encircled the capital of Bogota, yet they were subsequently been pushed back to the southern highlands of the country and into the surrounding borders of Ecuador and Bolivia. As a result, FARC attacks in Colombia have declined significantly. Bombings on Occidental Petroleum's Caño Limón pipeline—a frequent target of the FARC—for instance, reached 178 separate incidents in 2001 compared to just 57 in 2007. Even as the FARC have lost power and subsequently