Plant Protection

Deformed wing virus (DWV) is one of the most widespread viral infections of European honey bee Apis mellifera L. worldwide. So far, this is the first study which tested the effect of different ratios of synthetic protein to fat (P : F) diets on the health of broodless nurseaged honey bees in the laboratory. The aim of the current study was to determine the load of DWV in the whole body of A. mellifera that were fed different ratios of P : F diets (25 : 1, 10 : 1, 5 : 1, 1 : 1, 1 : 5, 1 : 10, 1 : 12.5 and 1 : 0 as a control). The methods involved feeding bees the tested diets for 10 days and then measuring the virus titre using qPCR technique. The results showed that DWV concentration decreased as the fat content of diets consumed increased. The copy number of viral genomes declined from 7.5 × 105 in the zero-fat diet (1 : 0) to 1.6 × 102 virus genomes in 1 : 12.5 (P : F). We can conclude that there is a positive relationship between fat diets and bee immunity and overall results sug...

This study has been conducted in the Faculty of Agriculture University of Kufa. The main objective of the current study is to see the effect of some natural products (plant extracts and honey) which are commonly used in the folk medicine in Iraq for their impact on the memory. We tested Arabic gum, rosemary, coriander and different types of honey on the learning and memory of honey bees. The results of the current study showed that the natural products that have been used had an impact on the learning and memory of workers honey bees compared to 1M sucrose as a control. The highest rate of learning was from multiflower honey followed by the coriander extract, then Eucalyptus honey, where they reached 58.8, 57.6 and 56 % respectively, while it reached 51.2, 48.4, 46.8% for the Arabic gum, desert honey and the aqueous extract of rosemary leaves respectively compared to 30% in control. The results also showed that the natural products had an impact on the nervous system of honey bee wo...

BACKGROUND: Potassium ion channels play a critical role in the generation of electrical signals and thus provide potential targets for control of insect pests by RNA interference. RESULTS: Genes encoding the small conductance calcium-activated potassium channel (SK) and the voltage-gated potassium channel (SH) were knocked down in Tribolium castaneum by injection and oral delivery of dsRNA (dsTcSK and dsTcSH, respectively). Irrespective of the delivery mechanism a dose-dependent effect was observed for knockdown (KD) of gene expression and insect mortality for both genes. Larvae fed a 400 ng dsRNA mg-1 diet showed significant gene (P < 0.05) knockdown (98% and 83%) for SK and SH, respectively, with corresponding mortalities of 100% and 98% after 7 days. When injected (248.4 ng larva-1), gene KD was 99% and 98% for SK and SH, causing 100% and 73.4% mortality, respectively. All developmental stages tested (larvae, early-and late-stage pupae and adults) showed an RNAi-sensitive response for both genes. LC50 values were lower for SK than SH, irrespective of delivery method, demonstrating that the knockdown of SK had a greater effect on larval mortality. Biosafety studies using adult honeybee Apis mellifera showed that there were no significant differences either in expression levels or mortality of honeybees orally dosed with dsTcSK and dsTcSH compared to control-fed bees. Similarly, there was no significant difference in the titre of deformed wing virus, used as a measure of immune suppression, between experimental and control bees. CONCLUSION: This study demonstrates the potential of using RNAi targeting neural receptors as a technology for the control of T. castaneum.

Iraq now ranks the 7th among world date producers and date palm syrup (DPS) produced from palm date tree, Phoenix dactylifera L. is a traditional syrup used by Iraqi people during winter because of its availability and cheapness. The present study aimed to use DPS as a honey substitute for feeding honeybees at nectar shortage. This study was conducted in the bee laboratory at the University of Kufa, Faculty of Agriculture in 2021. Experiments comprised studying the effect of DPS on honeybee nutritional behaviour, survival and nutrient contents (protein, fat and ash) of honeybee body. Four treatments of DPS dissolved in 1M sucrose were used; 5, 25, 75 and 100% DPS as well as 1M sucrose and honey as-ve and +ve control, respectively. The results from the study indicate that bees generally preferred DPS reaching the highest consumption,75.7 µl/bee/day at 100% concentration, compared to 22.81 µl/bee/day in the-ve control (1M sucrose) and 24.5 µl/bee/day in the +ve control (honey). Furthermore, the best bee survival was 97.8% at 25% DPS and the lowest was 41.8% at 100% DPS compared to 95.8% at-ve control and 96% at +ve control. Regarding the bee body composition of some nutrients, the present results indicated that there was no significant difference among most treatments reaching the highest protein content in 1M sucrose, 52.6 mg/bee, compared to 33.9 mg/bee at 5% DPS. There was a negative correlation between fat content and DPS, as the highest fat content 9.3% was seen at 5% DPS, while it was 2.5% at 100% DPS compared to 8.7-12.6% at-ve and +ve controls. In contrast, the ash content of the bee body was at the highest in 100% DPS reaching 11.9 gm/ bee compared to 6.5 gm/bee at 5% DPS, while it was 3.9-4.2 gm/bee at-ve and +ve controls. In conclusion, DPS can be used in honeybee feeding in absence of natural resources.

This study aimed to evaluate the nutritional behavior and some immunological criteria (encapsulation index and phenoloxidase-PO activity, the key enzyme for melanization) as well as to study the effect of protein to fat (P : F) diets on hypopharyngeal gland (HPG) protein content. Bees were restricted to consuming specific P : F diets varying in fat ratio under laboratory conditions. These diets included 25 : 1, 10 : 1, 5 : 1 (low-fat diet, LFD); 1 : 1 (equal-fat diet); 1 : 5, 1 : 10 (high-fat diet, HFD), and 1 : 0 (zero-fat diet) as a control. Bees preferred low-fat diets over high-fat diets, where it was 11.27 ± 0.68 µl • day-1 bee in 10 : 1 P : F, while it was 4.99 ± 0.67 µl • day-1 bee in 1 : 10 P : F. However, sucrose consumption was higher in high-fat diets where it was 25.83 ± 1.69 µl • day-1 bee in 10 : 1 P: F, while it was 30.66 ± 0.9 µl • day-1 bee in 1 : 10 P : F. The encapsulation index and phenoloxidase activity of bees were positively linked with the fat level they consumed during all 10 days. The maximum percentage of encapsulation index was 74.6 ± 7.2% in bees fed a high-fat diet, whereas the minimum percentage was 16.5 ± 3.6% in bees which consumed a lowfat diet. Similarly, phenoloxidase activity increased in the haemolymph with increasing fat consumed by bees (0.001 ± 0.0001 and 0.005 ± 0.0003 mM • min-1 • mg-1 at 25 : 1 and 1 : 10 P : F, respectively). The protein content of hypopharyngeal glands in bees which consumed HFD was double that of LFD. Overall results suggest a connection between a fat diet and bee health, indicating that colony losses in some cases can be reduced by providing a certain level of fat supplemental feeding along with sucrose and protein nutrition.