1 A 2-year study was conducted aiming to characterize the spatio-temporal association of spotted alfalfa aphid Therioaphis maculata Buckten (Hemiptera: Aphididae) and Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae) in alfalfa fields. 2 The present study was conducted in 0.5-, 3.1-and 7.3-ha alfalfa fields and at two spatial scales. The 0.5-ha field was divided into 10 × 10 m grid; and the 3.1-and 7.3-ha fields were divided into 30 × 30 m grids. Weekly samplings began when plant height reached approximately 15 cm and were continued until hay cutting. Forty and ten stems were chosen randomly in 30 × 30 m and 10 × 10 m grids, respectively. The stems were shaken into a white pan three times and the aphids and coccinellids fallen in the pan were counted. 3 The data were analyzed using spatial analysis by distance indices. Both T. maculata and H. variegata showed aggregative spatial pattern. The results also revealed that there was a positive spatial association between spotted alfalfa aphids and lady beetles. 4 Spatio-temporal synchrony between predator and prey distribution is important with respect to implementing biological control. Therefore, the findings of the present study can be used in the conservation of natural enemies, site-specific spraying against spotted alfalfa aphid and the effective management of this pest.

BACKGROUND Mediterranean flour moth or mill moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) is a common pest of cereals and flour throughout the world. In this study, eggs, third instar larvae, pupae and adults of E. kuehniella were exposed to five elevated temperatures at a range of 45 to 65 °C for 5, 8, 10, 14, 18, 23 and 30 min. The effect of cypermethrin and dichlorvos was assessed on third instar larvae. The larvae were exposed to the insecticides on glass and concrete arenas and their mortality was recorded 24 h after treatment. To determine combination effects, the third instar larvae were transferred into the Petri dishes treated with LC25 (lethal concentration that kills 25%) of each insecticide and exposed to high temperatures for the period of time equal to LTi25 values (time needed for killing 25% of tested insects). RESULTS Exposing the eggs, third instar larvae and adults of E. kuehniella to 55 °C for 30, 18 and 30 min respectively, resulted in 100% mortality. In the pupa, exposure to 65 °C caused 100% mortality after 23 min. Based on the LTe50 values (temperature needed to cause 50% mortality in the tested population), pupa was the most tolerant life stage to the temperatures tested. The LC50 values of cypermethrin and dichlorvos were 423.1 and 2608.5 mg active ingredient (a.i.) L−l on glass, and 2525.0 and 13502.8 mg a.i. L−l on concrete, respectively. The effect of cypermethrin was synergized by high temperatures. CONCLUSION High temperatures, cypermethrin and dichlorvos were effective against E. kuehniella. Exposure to combination of lower doses of cypermethrin and high temperatures at short time intervals may have potential in managing this pest. © 2021 Society of Chemical Industry.

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