Weeds as Reservoirs of Beneficial Insects to Control Pests in Crops

Although aphids are pests and can cause 100% crop loss, they also are food for natural enemies and birds. The objective of this work was to determine predators and parasitoids of aphids and agroecological characteristics of weeds. The study was done in monocultures of intensive agriculture at El Copal Irapuato. Twenty-two plant species were collected, predominantly Asteraceae with eight species; nine species of aphids were collected. Aphis craccivora Koch was on four plant species. Aphidius colemani Viereck parasitized as many as 84% of Uroleucon ambrosiae (Thomas). Allograpta oblicua (Say), Pseudodorus clavatus (F.), and Paragus tibialis (Fallen) hoverflies were found in larvae preying on aphids. The larva of Micromus posticus (Walker) fed on aphids, the first record of immatures of the species of Hemerobiidae in the State of Guanajuato. Other species of predators were reported.