B. Hatami, K. Zibai,
Volume 4, Issue 3 (fall 2000)
Abstract
The interference of biological agents may cause behaviors such as interspecific predation, reducing their efficiencies. The interspecific predation of lacewing, Chrysoperla carnea (Steph.) and ladybeetle, Hippodamia variegata (Goeze) was investigated in the presence and absence of prey, Aphis gossypii Glover under laboratory conditions.
In the presence and absence of prey, the larvae of lacewing fed on eggs, larvae, pupae and adults of ladybeetle and the larvae and adults of ladybeetle fed on eggs and larvae of lacewing. Presence of prey reduced the rate of feeding significantly. Feeding of lacewing larvae on ladybeetle eggs was higher than the feeding of ladybeetle larvae and adults on lacewing eggs. This is probably due to the stalk of lacewing eggs. The 1st larval instar of lacewing was dominant to that of ladybeetle, so were 2nd larval instar of lacewing to the 1st and 2nd larval instars of ladybeetle and 3rd larval instar of lacewing to all larval instars and adults of ladybeetle. Third larval instar of ladybeetle was dominant to the 1st larval instar of lacewing, and 4th larval instar and adult of ladybeetle to the 1st and 2nd larval instars of lacewing. The 2nd and 3rd larval instars of lacewing fed on pupa of ladybeetle but larval feeding of ladybeetle was not observed on lacewing pupa. This was probably related to lacewing pupa covered by a cocoon.
K. Zibai, B. Hatami,
Volume 4, Issue 4 (winter 2001)
Abstract
The efficiency of singular and joint usage of third larval instars of ladybeetle, Hippodamia variegata (Goeze) and green lacewing, Chrysoperla carnea (Steph.) was studied against cotton aphid, Aphis gossypii Glover on cucumber plants in greenhouse.
The predator-prey ratio of 1:30 reduced the population of pest significantly. Singular and joint usage of predators, however, was not significantly different. The predator-prey ratio of 1:90 reduced the population of host significantly but the treatment with larvae of both predators and the treatment with only ladybeetle larvae were not significantly different. However, only the treatment with lacewing larvae was significantly different from the two above-mentioned treatments.
M. Sabohi, Gh. Soltani, M. Zibaie,
Volume 11, Issue 1 (spring 2007)
Abstract
The objective of this study was to evaluate the strategies for groundwater resources management, including competition groundwater pumping, optimal control in groundwater pumping, groundwater use and tax policy, water users' participation in groundwater pumping control, and cooperation among government and water user associations in Narimany plain located in Khorasan Province. Irrigation water demand of sugar beet growers was estimated for empirical assessment of the strategies. The results indicated that among the strategies, groundwater use and tax policy may lead growers to sustainable use of groundwater resources. Furthermore, the results showed a desirable strategy is affected by cultural, social, and economic characteristics of growers and general prevalent conditions of society. Moreover, each strategy calls for its obligations, for instance, it is necessary to have an efficient taxation system for the proposed strategy. Hence, by internalizing the external cost of groundwater overdraft (that is taxing water users) government can force them to consider the adverse effects of their decisions on other producers.
