Spodoptera exigua (Lepidoptera: Noctuidae) is one of the major pests of many crops in Pakistan. Effectiveness of different insecticides was evaluated against field populations of 2 instar larvae of S. exigua under laboratory conditions because in lepidopterous pests resistance is developed in 3 instars. Bioassays were performed through leaf dip method to evaluate the doseand time-mortality resp...

We studied the mechanism of cold acclimation of Jerusalem artichoke (Helianthus tuberosus L.) tubers with special reference to the role of the cell wall. During the cold-acclimation process from September to January, the freezing tolerance of tubers increased from -2.8 degrees C to -8.4 degrees C (LT50). By contrast, the isolated protoplasts constitutively showed a consistent high level of free...

Fumigant toxicity and sublethal effects of essential oils from Artemisia khorassanica Podl. and Artemisia sieberi Bess were investigated against adults of Sitotroga cerealella Olivier. To assess the sublethal effects, adult moths were exposed to the LC30 of each essential oil, and life table parameters of the surviving S. cerealella were studied. Higher fumigant toxicity of A. khorassanica (LC5...

When alfalfa (Medicago sativa L. cv Apica) plants grown at room temperature are transferred to 2 degrees C, the temperature at which 50% of the plants fail to survive (LT50) decreases from -6 to -14 degrees C during the first 2 weeks but then increases to -9 degrees C during the subsequent 2 weeks. However, when plants are kept for 2 weeks at 2 degrees C and then transferred to -2 degrees C for...

The repellency and toxicity of mint oil to American, Periplaneta americana (L.), and German, Blattella germanica (L.), cockroaches were evaluated in a series of laboratory experiments. In topical application experiments, mint oil was toxic to both species with toxicities (LD50s) of 2.57 (1.98– 4.20) in 10 l and 3.83 (2.35–7.34)% in 2 l for American and German cockroaches, respectively. In conti...

Spilarctia obliqua nucleopolyhedrosis virus (SoNPV) has been found effective against S. obliqua (Walker) as well as Porthesia xanthorrhoea Kollar. LC50 concentration of S. obliqua SoNPV against S. obliqua and P. xanthorrhoea was 2.5 x 10(4) and 3.7 x 10(4) POBs/ml, respectively. LT50 of SoNPV against S. obliqua was 5.73 days, while it was 6.98 days for P. xanthorrhoea. Cross infectivity of SoNP...

Context The ability of ectothermic stream invertebrates to adapt the predicted increases in mean and extreme temperatures is crucial ensuring they continue exist.Aims To examine plasticity thermal limits Australian Paratya spp. (Decapoda, Atyidae) from streams eastern New South Wales (NSW). We hypothesised that upper lethal temperature (ULT, as indicated by median temperature, LT50) would be hi...

ABSTRACT Parental effects can prepare offspring for different environments and facilitate survival across generations. We exposed parental populations of the estuarine anemone, Nematostella vectensis, from Massachusetts to elevated temperatures quantified larval mortality a temperature gradient. found that exposure resulted in consistent increase thermal tolerance, as measured by at which 50% l...

In the present work we have evaluated the acute toxicity of two anionic surfactants, alkyl benzene sulphonate (ABS) and sodium dodecyl sulphate (SDS) to eggs of gilthead Sparus aurata. At each surfactant concentration, we determined the exposure time required for 50% mortality of the eggs (LT50), surface tension and volume of oil globule in gilthead eggs. Clear dose-response relationships for m...

The white grub Laniifera cyclades Druce of prickly pear cactus or nopal is a pest that limits the commercial production of Opuntia . The gregarious larvae perforate the cladodes devouring the inner part, thereby forming large galleries until reaching the central axis of the plant; during their movement through the inner part of the cactus, the larvae make orifices to the exterior to expel their...