03395naa a2200325 a 450000100080000000500110000800800410001910000160006024501250007626000090020130000160021049000080022652023630023465000230259765000260262065000240264665000240267065000120269465300290270665300270273565300270276265300250278965300220281465300250283665300270286165300270288870000170291570000210293277301160295314626192010-07-06       2000    bl uuuu     u00u1 u    #d1 aM0RALES, L.  aEnhancement of Anticarsia gemmatalis (Lepidoptera the Mechanisms Noctuidae) baculovirus activity by optical brighteners.  c2000  ap.1048. v.2  vv.2  aThe nucleopolyhedrovirus of the velvetbean caterpillar Anticarsia gemmatalis (AgMNPV) has been used as a microbial pesticide in Brazil since the 1980/81 and in the 1998/99 season more than 1.0 million ha have been treated with the pathogen. Some intrinsic characteristics of nucleopolyhedrovirus such a slow action in killing the hosts limit farmers acceptance of the virus as well as the expansion of their use as microbial insecticides. In addition, Brazilian populations of A. gemmatalis submitted to selective pressure under laboratory conditions, developed high resistance to the virus denoting possibility for resistance when used extensively in the field. Among the strategies to reduce time to kill the hosts or to counteract resistance, mixing substances that enhance viral activity seems to be a viable one. Optical brighteners (=fluorescent brighteners) used in papers, laundry detergents, plastics, and coating industries, demonstrated to protect nucleopolyhedrovirus against ultraviolet light and also, affected larval mortality rates. Four optical brighteners were evaluated in combination with A. gemmatalis nucleopolyhedrovirus in both, susceptible and resistant insects. The brighteners Tinopal UNPA-GX, Tinopal DMS, Leukophor DUB, and BRY 10 D2 100 were used at a 0.5% concentrations and added to the AgMNPV in concentrations ranging from 10 to 1x10 9 occlusion bodies (OBs)/ml. The most effective brightener (Tinopal UNPA-GX)reduced the LC 50 from 7083.0 OBs/ml to 77.8 OBs/ml (ca.90-fold) in susceptible insects and from 3.7x10 7 OBs/ml to 6x10 2 OBs/ml (ca. 62,000-fold) in resistant insects. The mean time to mortality was reduced ca. 30% with AgMNPV/Tinopal UNPA-GX group. The four brighteners all belonging to the stilbene group, significantly enhanced the A. gemmatalis larvae mortality by AgMNPV - in resistant A. gemmatalis larvae, optical brighteners were more effective than in susceptible ones-, reduced the mean time of mortality and none showed negative effects against A. gemmatalis larvae, when used alone. These results indicate that brighteners may be useful substances to be included in formulations of the AgMNPV, either to increase activity and speed of kill ofthis biological insecticide or to counteract cases of resistance of A. gemmatalis to the AgMNPV that eventually may developin field population of this insect.  abiological control  aAnticarsia Gemmatalis  aControle Biológico  aControle Microbiano  aLagarta  aBranqueador fluorescente  aEntomopathogenic virus  aFluorescent brightener  aInseticida biologico  aMicrobial control  aPesticida microbiano  aVelvetbean caterpillar  aVirus entomopatogenico1 aMOSCARDI, F.1 aSOSA-GOMEZ, D.R.  tIn: INTERNATIONAL CONGRESS OF ENTOMOLOGY, 21., 2000, Foz do Iguassu. Abstracts... Londrina: Embrapa Soja, 2000.