Publications

Titles

English :

Effect of simulated infestation levels caused by leaf feeding larvae on Soybean plant traits and crop yield

Arabic :

تأثير مستويات الإصابة بديدان الورق على صفات وإنتاج محصول فول الصويا

Abstract

Cotton leafworms Spodoptera littoralis and S. exigua are considered the main leaf feeding larvae on soybean fields in Egypt. Four experiments in 2 successive years (2001-2002) were conducted in Sakha and Sids to study the simulated defoliation levels on some plant traits (Plant-height, number of branches & pods) and crop yield. In season 2001, plant height was significantly affected with the different levels of the daraage. Number of branches significantly affected at Sids region, while at Sakha the opposite was found. As for number of pods, there is no significant difference in both regions. However, mean number of seeds and seed weight/plant were signifícantly affected at Sids while were not at Sakha. The modifïable experiments in season 2002 were conducted at both regions, using 6 levels of simulated defoliation (20, 30, .... 80%) which applied on four different plant growth stages of variety Giza 21. In addition to the criterion data of season 2001, the weight of 100-seed & yield/feddan and the expected percent of yield reduction due to the different levels of damage were calculated. At Sids, in season 2002, plant height was not signifïcantly affected by each treatment on the four plant growth stages. 20% level increased the height among the four plant stages. While the highest effect on reducing the heights was found with 60% and 80% level of damage. However, at Sakha, a significant difference was found among the plant stages. The more increase of simulation levels of damage the higher reduction in height was found. For number of branches, generally, the law defoliation levels were effective on increasing the number of branches in both regions to compensate the vegetative loss. However number of pods/plant, 100-seed weight and seed yield showed a highly significantly affected by the different levels of-damage in both regions. In general the percent yield losses due to the different damage levels of leaf area showed that, the reduction in yield increased upward according to the level of damage, and reached the highest with the R5+R6 stage (beginning seed).

Publication year

2003

Pages

607-620

Availability location

معهد بحوث وقاية النباتات

Availability number

Organization Name

Plant Protection Research Institute (PPRI)

City

القاهرة

serial title