Corn leaf aphid, Rhopalosiphum maidis (Fitch) is one of the most serious corn pests in Egypt. The aim of the present study is to assess the corn yield losses and to build forecasting models of yield related with aphid infestation. Number of aphids/plant were determined during corn growth stages 10 leaves (V10); tasseling (VT); ripening 2 (R2) and ripening 4 (R4). At the end of growing season, yield losses were estimated. Results revealed that infestation with aphids through V10-VT caused 28.14% yield losses at average aphid density 818 aphid/plant. Infestation through R2-R4 caused 16.28% yield losses at average aphid density 1038 aphids/plant. Percentages of yield losses of corn ears through V10-R4 were 14.66, 22.9, 35.28 and 36.03% at average aphid density of 100, 1000, 2000 and 3000 aphids/plant. As ear yield negatively correlated with aphid density, regression analysis was used to construct forecasting yield models. Statistical analysis showed that simple linear and logarithmic models provided a good fit to the data and also indicated that the two models are similar in prediction of ear yield. These constructed models were diagnostic checked using new data. The checking revealed that the linear model is stable and valid where insignificant difference was observed between predicted and actual yield.

A two-year field study was carried out at the Agricultural Experiment Station, Alexandria University in 2017/2018 and 2018/2019 winter seasons to investigate the effect of foliar spraying of humic acid (HA) (0 and 2.4 kg/ha) and both Fe and Zn micronutrients (0, 480 and 960 g/ha of FeSO4 and/or ZnSO4, respectively) on three durum wheat cultivars (Casino, Bani Sweif6 and Sohag3). The experiment was laid out in split-plot design with three replications, where combinations of HA levels and cultivars occupied the main plots, while combinations of Fe and Zn levels were randomly allocated to the sub plots. Bani Sweif6 was superior to the other two cultivars for all studied grain yield and yield components except for 100-grain weight. Application of humic acid increased grain yield of Bani Sweif6 and Sohag3, but negatively affected that of Casino. Application of 480 g/ha of both FeSO4 and ZnSO4 gave the highest values with HA application in Bani Sweif6 and Sohag3, and without HA application for Casino. It is recommended to spray Bani Sweif6 and Sohag3 with 2.4 kg/ha HA and 480 g/ha of both Fe and Zn, while more studies are needed to determine the suitable level of HA spraying for Casino cultivar.

This study was carried out in 2017 and 2018 seasons to investigate effect of nutrient mixture and potassium levels applied as spray or to soil on sunflower yield and its components using split-plot design with four replicates. Main plot treatments were: K1 (control) without K, K2: 57 kg K2O/ ha, K3: 114 kg K2O/ ha (K1, K2 and K3 as soil application), K4 (control): spraying with tap water, K5: 0.58 kg K2O/ ha and K6: 1.16 kg K2O/ ha (K4, K5 and K6 as foliar application). Sub-plot treatments were 0, 1 and 2 liters of nutrients mixture per hectare. K5 treatment produced the heaviest heads(132.0g),highest seed weight/ head(69.98g)in the first season and highest oil (41.33%) without significant differences with potassium soil application treatments in that season. (K6) produced the thickest stems(2.28 and 2.31cm)in both seasons, largest head (20.54cm), heaviest heads (122.49g), highest shelling (52.81%) and heaviest 100-seed weight (8.26g) in the second season, whereas (K5 and K6) treatments gave the heaviest seed weight/ head (60.99 and 64.70 g), and highest shelling (53.03 and 53.02%) in the first season and seed yield/ ha (3.35 and 3.55ton) in the second season. Foliar application of nutrients mixture significantly increased all the studied treatments, except head diameter in 2017, stem diameter, 100-seed weight and oil percent in 2018 season. Interaction had significant effect on plant height, head weight, shelling % and harvest index in both seasons. K5 and/ or K6 combined with nutrient mixture foliar application, generally, increased the aforementioned traits under Alexandria Governorate.

Two field experiments were conducted during the 2013 and 2014 summer seasons to investigate the effect of planting dates and planting patterns on productivity and quality characters of Egyptian cotton cultivar Giza 86 (Gossypium barbadense L.). Effects of planting date were more pronounced on the studied phenological characters, yield and yield components than the planting patterns. The fiber technological traits including micronaire-reading, fiber maturity, fiber upper half mean length (UHML), uniformity index (UI), short fiber (SF) and fiber strength (Str.) were least affected by either planting dates or planting patterns. Results suggest that growing cotton on the 1 st of April is more suitable than delayed sowing for the cultivar Giza 86 and that the standard sowing of seeds on one side of the ridge, in hills 25 cm apart, resulted in better growth characters and highest yields. Also growing cotton on the wide ridges of the preceding wheat crop is not recommended as it resulted in reduction in yield and its components.