Date Palm Orchards Research Articles

Impacts of aquaculture wastewater irrigation on soil health, nutrient availability, and date palm fruit quality

Water scarcity and droughts are among the most challenging issues worldwide, particularly in arid and semi-arid regions like Saudi Arabia. Date palm (Phoenix dactylifera L.), a major crop in Saudi Arabia, is being significantly affected by water scarcity, soil salinity, and desertification. Alternative water sources are needed to conserve freshwater resources and increase date palm production in Saudi Arabia. On the other hand, Saudi Arabia has a significant number of aquaculture farms that generate substantial amounts of wastewater, which can be utilized as an alternative source of irrigation. Therefore, this study aimed to assess the potential of aquaculture wastewater as an alternative irrigation source for date palm orchards. Aquaculture wastewater was collected from 12 different farms (Al-Kharj, Al-Muzahmiya, and Al-Qassim regions, Saudi Arabia) and its quality was analyzed. The impacts of aquaculture wastewater irrigation on soil quality, nutrient availability, nutrient status of date palm trees, and dates fruit quality were assessed in comparison to source water (freshwater) irrigation at Al-Kharj, Al-Muzahmiya, and Al-Qassim regions. The water quality analyses showed higher salinity (EC = 3.31 dSm−1) in farm Q3, while all other farms demonstrated no salinity, sodicity, or alkalinity hazards. Moreover, the aquaculture wastewater irrigation increased soil available P, K, NO3−–N, and NH4+–N by 49.31%, 21.11%, 33.62%, and 52.31%, respectively, compared to source water irrigation. On average, date palm fruit weight, length, and moisture contents increased by 26%, 23%, and 43% under aquaculture wastewater irrigation compared to source water irrigation. Further, P, K, Fe, Cu, and Zn contents in date palm leaf were increased by 19.35%, 34.17%, 37.36%, 38.24%, and 45.29%, respectively, under aquaculture wastewater irrigation compared to source water irrigation. Overall, aquaculture wastewater irrigation significantly enhanced date palm plant growth, date palm fruit quality, and soil available nutrients compared to freshwater irrigation. It was concluded that aquaculture wastewater can be used as an effective irrigation source for date palm farms as it enhances soil nutrient availability, date palm growth, and date fruit yield and quality. The findings of this study suggest that aquaculture wastewater could be a viable alternative for conserving freshwater resources and increase date palm production in Saudi Arabia.

The influence of temperature, light, pH and salinity on germination and growth of Cutandia memphitica (Spreng.) Benth

Background: There are many weed species that affect yield and quality in date palm orchards. Cutandia memphitica (Spreng.) Benth. is one of the weeds that is common in date palm orchards in Iraq. However, there is not enough information about C. memphitica in the literature. In order to provide information about the effect of key environmental factors (temperature, light, pH, and salt) on the seed biology of this weed species, this study was conducted.Methods: Within 2020, seeds were collected from agricultural regions in southern Iraq, and trials were done at Erciyes University Faculty of Agriculture labs in Kayseri Türkiye. All experiments were carried out with 30 seeds in the sterile 90 mm (90×15) petri dishes containing two layers of sterile filter paper.Results: The results of this investigation revealed that the seeds of this species germinated by 72.49% in three days when incubated at 25°C, and by 96.66% in 14 days when incubated at 15°C. The results also indicated that even during the longest incubation time examined, which was 28 days, the seeds of this species never germinated at 30 degrees or above. They can germinate during this period if kept at 5°C. The study also revealed that 90% of the seeds of this species germinated in complete darkness, whereas only 11.66% germinated in light. However, light has a significant impact on studied growth parameters (plant height and seedling fresh and dry weight). The results also demonstrate that the pH levels examined, which varied from 4 to 10, had no effect on the seed germination and growth parameters of seedling.Conclusion: The results showed that the seeds of this species germinated at the highest salinity levels (250 mM NaCl) by 10.83%. Meanwhile, the best germination was recorded at 25 mM salinity level of 89.16%, but without significant differences with salinity level at 50 mM and control. Also, the growth indicators were reduced significantly at the salinity level of 250 mM compared to the control.Keywords: Light; Salinity; Seed Germination; Temperature; Weed; Date Palm

Assessing the toxicity of six insecticides on larvae of red palm weevil under laboratory condition

ObjectiveThe red palm weevil (RPW), is one of the most threatening pests of date palm trees worldwide, causing significant economic losses annually for date palm growers, both globally and in the Middle East, including Saudi Arabia. The primary objective of this research was to assess the insecticide market in Saudi Arabia, test various insecticides claimed to be effective against RPW, and evaluate their efficacy in laboratory settings. This evaluation aims to inform further trials under field conditions. MethodsSix insecticides, including imidacloprid, thiamethoxam, fipronil, emamectin benzoate, deltamethrin, and fenitrothion, were tested to assess their toxicity against red palm weevil 8th instar larvae by diet incorporation under laboratory conditions. The insecticides were applied according to the manufacturer’s recommendations with dosages of 1000 µl, 0.20 µl, 7.5 µl, 0.25 µl, 0.25 µl, and 0.5 µl for imidacloprid, thiamethoxam, fipronil, emamectin benzoate, deltamethrin, and fenitrothion, respectively. ResultsThe results revealed that all tested insecticides exhibited 100 % mortality against 8th instar RPW larvae, with the exception of deltamethrin. However, the time required to achieve this mortality varied. Fenitrothion caused 100 % mortality after 72 h, while thiamethoxam, imidacloprid, and fipronil caused 100 % mortality after 96 h. Emamectin benzoate and deltamethrin resulted in 100 % and 93 % mortality, respectively, after 10 days. The variability in mortality rates may be attributed to differences in their active ingredients, which show varying levels of lethality. In conclusion, all tested insecticides showed effectiveness against RPW larvae and represent viable options for controlling this pest in date palm orchards in Saudi Arabia.

Managing Dust Mite Oligonychus afrasiaticus (McGregor) (Acari: Tetranchidae) Infesting Date Palm Orchards By Using Lemongrass Extract and Nanosulfur

The dust mite Oligonychus afrasiaticus (McGregor 1939) (Acari: Tetranychidae) poses a significant threat to date palm Phoenix dactylifera L. productivity in Iraq. To address this issue, a field study was conducted in a private date palm orchard in Al-Zubair district, Basrah province, Iraq, to assess the efficacy of some treatments in controlling the dust mite population on date palm fruits. The treatments included lemongrass extract, nanosulfur, a combination of lemongrass extract and nanosulfur, liquid sulfur, and a distilled water as control treatment. Treatments were applied by spraying on leaves and fruits at three dates: five weeks, eight weeks, and eleven weeks after pollination. Dust mite mortality rates were measured at intervals of 1, 3, 5, and 7 days after treatment application. Results revealed that the second date, eight weeks after pollination, exhibited the highest mortality rate of 76.77%, significantly outperforming other dates. Among the treatments, liquid sulfur showed the highest efficiency, with an 87.83% mortality rate, followed closely by the combination of lemongrass extract and nanosulfur (84.14%). Nanosulfur alone recorded a mortality rate of 79.26%, while lemongrass extract alone showed a mortality rate of 49.15%. The mortality rate increased over time, reaching 80.79% after 7 days and 65.76% after 1 day. In conclusion, liquid sulfur emerged as the most effective treatment for controlling the dust mite population on date palm fruits. The second date, eight weeks after pollination, was the optimal time for treatment application. These findings offer valuable insights into sustainable and environmentally friendly pest control strategies for date palm cultivation in Iraq.

المكافحة الحيوية لآفة الحميرة (Batrachedra. Amydraula/ mayrick) باستخدام الطفيل المحلي طفيل الجينوزس Goniozus omanensis

GONIOZUS OMANENSIS (Hym. Bethylidae) has been found to be the most common parasitoid of the lesser date moth, Batrachedra amydraula not only in Sultanate of Oman but also in neighboring Gulf states and other date palm growing parts of the world. It is one of the most important pests on date palm that is reported to cause more than 50% loss of the crop. Batrachedra amydraula, the lesser date moth is a species of moth of the Batrachedridae family reported from Bangladesh to western Saudi Arabia, Yemen, Israel, Iraq, and Iran, as well as most of North Africa. The larvae feed on Phoenix dactylifera. There are three generations per year in Sultanate of Oman. The first larvae appear in April and damage newly formed fruits. They are dormant from August to March of the following year, resting between the bases of the terminal fronds. Pupation takes place in March and adults emerge in April. Goniozus omanensis is primary parasitoid of lesser date moth Batrachedra amydraula. The present investigation involved successful rearing of parasitoid in the laboratory on larvae of Galleria mellonella and release in three date palm orchards as a bio-control agent against such a pest (one release, two releases, and three releases). The results showed that one release was sufficient to control 80% of the pest population in comparison with two (50%) and three releases (40%). About 0.1 % of pest was found from the bottom in comparison with emerging adults’ pests from infested fruits from the top of the palm.

Effect of Pollinator, Number of Pollination Times and Organic Fertilizer on Leaf Mineral Content and Yield of Barhi Date Palm

The experiment was conducted in 2022 in one of the date palm orchards of Barhi cultivar cultivated at Dawar palm station, Ministry of Agriculture / Horticultural Department, to study the effects of pollinator cultivar and decomposed organic fertilizer on yield and leaf mineral content of 54 drip-irrigated 7-year-old cultivar dates. A disease- and insect-free palm tree of consistent height and age, Factors of the study included adding two pollinator cultivars, Ghanaami Akhdar (P1) and local cultivar (P2), three times (N1), two (2 days after first pollination) (N2), and three times (3 days after first and 3 days after second) (N3). Decomposed organic fertilizer (sheep manure) was added in three levels (0, 20, and 40 kg.date-1), denoted by M0, M1, and M2. The factorial experiment in an RCBD employed 54 trees since treatments were reproduced three times (one date palm tree per experimental unit). The experimental results revealed that local cultivar pollinator (P2) enhanced fruit dry weight by 77.71% but did not affect leaf nitrogen, phosphor content, or fruit weight. Results revealed that pollination number did not substantially affect leaf nitrogen or phosphor content, but once (N1) showed considerable superiority in fruit dry weight of 78.10 % and fruit weight of 104.14 g. At 40 kg sheep dung, leaf nitrogen and phosphor increased considerably.date-1 (M2) had the maximum leaf nitrogen and phosphor content of 1.548% and 0.380 %, and fruit weight of 107.00 g. M1 had the highest fruit dry weight percentage of 78.95%. Triple interactions between study parameters strongly influenced all attributes.

Chemical control and herbicide resistance of hairy fleabane (Erigeron bonariensis L.) in Jordan.

The effect of paraquat, oxadiazon and oxyfluorfen herbicides was tested on two populations of hairy fleabane (Erigeron bonariensis L.), collected from a date palm orchard at Tal al-Ramil (Central Jordan Valley) and al-Twal (Northern Jordan Valley) sites using the recommended rates (0.5, 1.25 and 0.792kg a.i ha-1 for each herbicide, respectively) and 10-fold (5, 12.50 and 7.92 kg a.i. ha-1, respectively) under glasshouse conditions. Results showed that the date palm weed population was resistant to the three herbicides at both application rates and al-Twal site population was highly susceptible. Two field experiments were conducted to evaluate the effectiveness of 12 herbicides in controlling the weed in the date palm orchard during the spring of 2017, revealed that E. bonariensis resists paraquat (0.5, 1.0 and 1.5 kg a.i. ha-1), oxadiazon (1.25 kg a.i. ha-1) and oxyfluorfen (0.792 kg a.i. ha-1) herbicides. None of the three herbicides was effective against the weed and treated plants continued to grow normally similar to those of untreated control. Ten-fold higher rates of these herbicides failed to control the weed. The effect of other tested herbicides was variable with bromoxynil plus MCPA (buctril®M), 2,4-D- iso-octyl ester, glyphosate, glyphosate trimesium and triclopyr being the most effective and completely controlling the weed at recommended rates of application. It is concluded that the tested populations of E. bonariensis developed resistance to paraquat, oxadiazon and oxyfluorfen but control of the weed was possible using other herbicides with different mechanisms of action. Herbicide rotation or other nonchemical weed control methods have been suggested to prevent or reduce the buildup and spread of resistant populations of this weed. These results represent the first report of herbicide resistance of E. bonariensis in Jordan.

Acoustic Comparisons of Red Palm Weevil (Rhynchophorus ferrugineus) Mortality in Naturally Infested Date Palms after Injection with Entomopathogenic Fungi or Nematodes, Aluminum Phosphide Fumigation, or Insecticidal Spray Treatments.

Red palm weevil (RPW) management is important to the economic success of date palm agriculture. Monitoring with acoustic sensors was conducted in naturally infested trees in date palm orchards for six months after treatments with entomopathogenic fungi (Beauveria bassiana and Metarhizium anisopliae), entomopathogenic nematodes (Steinernema carpocapsae), aluminum phosphide, emamectin benzoate, or fipronil to evaluate their efficacy in an integrated pest management treatment vs. a distilled water injection. Reductions in the mean rates of RPW sound impulse bursts over time after treatment were used as indicators of RPW mortality. Entomopathogenic fungi and nematodes, aluminum phosphide, and emamectin benzoate were the most effective treatments, reducing RPW impulse burst rates within 2-3-months to levels indicating absence of infestation. However, when applied as a spray, fipronil had only a minor effect. The results indicate that treatments utilizing entomopathogenic fungi or nematodes can beneficially manage RPW in palm orchards and can help to limit treatments that may induce insecticide resistance or cause human and environmental harm. Furthermore, the use of an acoustic sensor can be beneficial in monitoring the activities of insect borers inside the tree trunk.

Genetic Variations among Fleabane (Conyza bonariensis (L.) Cronquist) Populations in Jordan and Their Susceptibility Levels to Contact Herbicides

A field demonstration and pot experiments were implemented to assess the effect of paraquat, oxadiazon, and oxyfluorfen herbicides in controlling selected populations of fleabane Conyza bonariensis (L.), grown in the central valley of Jordan. Conyza mature seeds were collected from six investigated sites (five from Jordan valley named P1, P2, P3, P4, P5, and one from the University of Jordan Campus named P6). Only populations proved to be C. bonariensis via ITS assessment were involved in the glasshouse experiments at the University of Jordan in 2017 and 2019. Results showed that recommended or two-fold higher rates (2.5 and 5 kg ha−1) of paraquat failed to affect weed plants in a date palm orchard located at Tal-al-Ramel in the Central Jordan Valley. Paraquat, oxyfluorfen, and oxadiazon (2.5, 3.3, and 5 kg ha−1, respectively), failed to control plants of the same weed population grown in pot experiments. Treated plants at Tal-al-Ramel grew similarly to untreated control, mostly due to different genetic backgrounds. The other C. bonariensis populations (University Research Station, al-Twal, and University Campus) were effectively controlled with all herbicides. The application of recommended or 10-fold higher rates of herbicides failed to control or slightly injured the resistant population. Seed DNA analysis of the ITS region showed genetic differences among the investigated populations. It indicated that four populations are C. bonariensis (P1, P3, P4, and P6). At the same time, two are C. canadensis (a closely related species) collected from the University Research Station (P2) and al-Twal sites (P5), and also that the population of C. bonariensis in the date palm orchard was genetically distinct from the other C. bonariensis populations. It is concluded that C. bonariensis population in the Tal-al-Ramel site developed resistance to paraquat, oxadiazon, and oxyfluorfen herbicides. Thus, novel alternative practices in controlling the resistant weed population are necessary to prevent its possible spread to other regions in the country and obstruct the development of new herbicide-resistance weed populations.

A survey of the date palm borers species and an estimate of their population density and relative presence in palm orchards in Salah Al-Din Governorate

A field study was conducted in date palm orchards in Salah al-Din Governorate during the period from 1/10/ 2020 to 30/10/2021 to survey the species of date palm borers and estimate their population density and relative presence during the study period. The results showed the diagnosis of three species of palm borers belonging to Coleoptera of the family Scarabaeidae, which included Oryctes elegans, Pentodon sp and Tanyproctus sp. The relative presence of males and females for the three borers was (53.00, 47.00%), (51.98, 48.02%) and (52.76, 47.24 %), respectively., the highest population density for males and females of the three borers during the month of June was (224, 192), (145, 132) and (68, 57) respectively, and the sex ratio for each of the three borers was 1.1:1 The highest total of adults caught by IPM Russell traps during one year was for O. elegans and Pentodon sp. it reached 418 and 236.3 adults/trap, respectively, while the total of adults of the two insects in the local trap was 75.7 and 49.9 adults/trap, respectively. For the borer Tanyproctus sp., the local trap superior on other traps , in which the total number of adults caught was 312 adults/trap, while it was 50 adults/IPM Russell trap.

Performance of Ferrolure+ pheromone in the red palm weevil, Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) management in date palm growing areas of Sindh, Pakistan

Red palm weevil (RPW), Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) has caused huge losses to date palm in Sindh province, main producer of dates in Pakistan. Due to lack of knowledge and availability regarding aggregation pheromones, mainly pesticides are used for its management. Therefore, seasonal monitoring of RPW was conducted at five talukas of Khairpur (Khairpur, KIngri, Kot Diji) and Sukkur (Rohri, Saleh Pat) districts of Sindh using Ferrolure+® (4-methyl-5-nonanol and 4-methyl-5-nonanone), ChemTica International, Costa Rica. Data was collected during pre-sucker transplanting season (after hibernation), main-sucker transplanting season (very active period due to the sucker transplantation) and post-sucker transplanting season (period after sucker’s plantation). Results indicated that significantly higher populations of RPW were recorded during main sucker planting seasons, followed by pre- and post-sucker planting seasons. Comparatively more RPW were captured at Sukkur than Khairpur during pre-sucker transplanting season only, whereas no significant difference in RPW captures was recorded during main- and post transplanting seasons. The sex ratio of captured females was almost double than males at all study locations during entire study. Relative humidity along with minimum and maximum temperature showed a significant effect on performance of Ferrolure+ to attract RPW. Therefore, use of Ferrolure+ pheromone traps should be included as the key integrated component in date palm orchards of Pakistan in general and Sindh in particular to keep the RPW below threshold.

Parallel Approaches Reaching One Target Red Palm Weevil Control Studies

Dates are major horticultural crop in Middle East region. It is the major fruit crop of arid deserts, in tropical and subtropical areas of the world including Gulf Cooperation Council of Northern Africa and Southern Asia. In Pakistan date palm are grown in four provinces. The area under cultivation of date palm is 98.7 thousand hectares with total production 735 thousand tons. The date palm of Sindh is mainly concentrated in district Khairpur and it is the biodiversity centre for the date palm having more than 300 varieties, which is also major date producing district of Pakistan. The Agriculture Extension Services play an important role in agriculture development by improving agricultural practices and adopting new production technologies in farming. The data used in this study was collected directly from date palm growers in district Khairpur using specially designed questionnaire. Data were collected through field survey in date palm growing area. The 60 growers in the study area were selected for this purpose. The Field survey was conducted regarding use of various inputs in date palm orchards, planting method of newly planted offshoots, irrigation, pollination, cultural practices, protection from pests & pathogens etc. The aim of present study was to conduct survey and to improve agricultural practices in date palm orchards & to disseminate information for production technologies to date palm growers. It was concluded from the survey that awareness level of the respondents varied too much for different aspects of crop and orchard management. In general not very large percentage of growers was aware of latest developments in the field. The study therefore recommends agricultural extension programs to date palm growers, stakeholders, researchers and Government. The data were analyzed using the statistical software SPSS. A secondary data source was also used to draw out results and suggestions.

Effects of Spraying with Urea and Seaweed Extract (Tecamin Algae) on Growth and Chemical Content of Date Palm Tree Cv. Zahdi

The following study was conducted in a private date palm orchard in the area of AlFurat, district of Heet throughout the season of 2019-2020 on 20-year-old date palm trees, Zahdi cultivar. The purpose was to study the effects of spraying the Urea compound with concentrations of (0, 1 and 2 g L-1) as well as seaweed extract (Tecamin Algae) with (0, 2 and 4 g L-1) of concentration on the growth and chemical content of the trees. 27 date palms were randomly selected. A factorial experiment with RCBD design was carried out such that it includes 9 treatments with 3 replicas for each treatment. Each tree was treated as one experimental unit. The results demonstrated that treatments of Urea spraying, especially with 2 g L-1 concentration, contributed to achieving the best results for response measurements (Leaf Area, Total Chlorophyll, Total Carbohydrates in the Leaflets, Nitrogen, and Phosphorous), which were (2.61 m2, 10.65 mg g-1, 7.46%, 1.69% and 0.40%), respectively. The content of phosphorous in the leaflets was not significantly affected when sprayed with Urea. On the other hand, seaweed extract spraying had a significant effect on all the response measurements. The 4 ml L-1 concentration gave the highest figures for our responses (total chlorophyll 10.38 mg g-1, Carbohydrates 7.52%, Nitrogen 1.65%, Phosphorus 0.37% and Potassium 0.67%). The concentration of (2 ml L-1) gave the largest area of the leaf at 2.63 m2.

Effect of increasing nitrogen fertilization on soil nitrous oxide emissions and nitrate leaching in a young date palm (Phoenix dactylifera L., cv. Medjool) orchard

The date palm (Phoenix dactylifera), an important agricultural crop in arid and semi-arid areas around the Mediterranean Sea, has high nutritional, cultural, and economic values. Date palm cultivation in Israel is practiced in the arid and hyper-arid Jordan and Arava Valleys and is associated with high water and nitrogen (N) fertilization inputs, with rates of up to ~170 m3 water and ~6 kg N per full-grown tree annually, on average. While the palm’s water needs and budget have been intensively studied, the fate of applied N has received little attention to date. Understanding this fate is especially important since high fertilization rates of ~740 kg N ha−1 may have deleterious effects on the environment. Specifically, soil emissions of nitrous oxide (N2O) and leaching of nitrate (NO3-) are of major concern, due to their impact on climate change and groundwater contamination. We have measured the effect of four levels of N fertigation (fertilization + irrigation), between 0 and 2.55 kg N tree−1 yr−1, on N2O and NO3- fluxes during an annual growth season in a three-year-old date palm orchard located in Israel’s hyper-arid Arava Valley. We used static chambers for soil N2O flux estimations and measured drainage water NO3- concentrations at a 60-cm depth, together with a Cl- mass-balance-based water budget to estimate the NO3- leaching. We observed trivial soil N2O emissions of up to ~0.02% of applied N, while NO3- leaching was estimated to be as high as 36%. Dry areas between the trees, which did not receive any fertilization or irrigation, exhibited even lower N2O emissions than the irrigated areas. Inorganic N, however, accumulated during the dry months in the upper layer of the soil and was later lost at the onset of the winter rains. Our results provide the first-ever estimations of the potential environmental impact of date palm plantations in Israel and the Mediterranean Sea Basin.

Water demand management for date palm orchards: the use of water pricing policy

Groundwater resources are the main source of water supply to the date palm orchards in Saravan County, Iran. The demand function is estimated using the Translog cost function and cost share equations of inputs. Results show that the real price of water is much more than the price paid by orchard owners. The substitution elasticity of water for the date crop shows its strong substitution with other inputs, but its price elasticity with other inputs is weak. In addition, the price elasticity is expectedly negative for water, but it is smaller than one and the demand (– 0.03) is inelastic.

Phenology and abundance of date palm mite Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) in Riyadh, Saudi Arabia.

In the present study, we evaluated the effect of management practices, fruit season, host habitats (young and old fronds, date fruits and grasses), and temperature on the phenology and abundance of the date palm mite (DPM). The study was conducted in two date palm orchards (two plots each): a managed and an unmanaged plot. The phenology of DPM was assessed based on adult cumulative mite days (ACMDs), while mean mite density was used to assess the mite abundance on different host habitats. The ACMDs and mean mite density were significantly different between managed and unmanaged plots on different host habitats in both fruiting and off-seasons. The date fruits had highest ACMDs during fruiting season. While young fronds had significantly higher ACMDs than on old fronds an grasses during both seasons in both plots.. The temperature and season type significantly affected the mean density of DPM eggs and adults. There was a significant effect of host habitats mean density of DPM eggs and immatures. Based on the adult phenology and abundance of DPM, the mite overwinters in young fronds and aerial offshoots of infested date palm trees. These overwintering DPM caused the seasonal date fruit infestation, each year. Additionally, different phytophagous and predatory mites, which co-occur with DPM, and were found on different host habitats affected the phenology and abundance of DPM. Moreover, the change in DPM body color was related to the host habitat that they fed in. Exceptionally, the brown color of females collected during the winter season could be due to physiological changes due to low temperature. In DPM males collected from different host habitats throughout the study, some morphological variations in the width of the knob, height of the hook, and the angle between the knob axis and dorsal margin of the shaft were also recorded. The results of this study suggest that young fronds and grasses are the suitable sites for DPM survival and overwintering. Hence, the management practices, early in the fruit season and/or during off fruit winter months, should be directed towards these habitats. These could provide efficient reduction in seasonal infestation of DPM.

Monitoring and Management of Date Palm Borers by Using Light Traps

Date palm borers become a serious threat to date palm plantations in Iraq, which required management program to suppress their population by using different methods; one of them is the light traps which disseminated in Basrah province. The objective of this trial is to evaluate the effectiveness of light traps as a part of pest management tool. In three years monitoring of coleopteran adults, rhinoceros beetles Oryctes spp. and longhorn date palm borer Jebusaea hammerschmidtii infesting the date palm Phoenix dactylifera were reported by using light traps in different regions of Basrah, Iraq. Due to the result of the abundance of the borers, Oryctes spp. were the most dominant and most important causing severe damage for the date palm. Four species of Oryctes (O. agamemnon, O. elegans, O. sahariensis and O. sinaicus) were recorded in Basrah date palm orchards; the seasonal activity of the species was between April and May, reaching the peaks during summer, and the populations decreased gradually till December. The overall sex ratios of all species of Oryctes spp. were male-biased except O. elegans, which had the sex ratio of 1.13 female: 1 male. Results revealed that the light traps exhibit an effective control method to suppress the adult borer’s population and as a physical control and monitoring tool of date palm stem borers.

Determination of Actual Evapotranspiration and Crop Coefficients of California Date Palms Using the Residual of Energy Balance Approach

As water scarcity becomes of greater concern in arid and semi-arid regions due to altered weather patterns, greater and more accurate knowledge regarding evapotranspiration of crops produced in these areas is of increased significance to better manage limited water resources. This study aimed at determining the actual evapotranspiration (ETa) and crop coefficients (Ka) in California date palms. The residual of energy balance method using a combination of surface renewal and eddy covariance techniques was applied to measure ETa in six commercial mature date palm orchards (8–22 years old) over one year. The experimental orchards represent various soil types and conditions, irrigation management practices, canopy characteristics, and the most common date cultivars in the region. The results demonstrated considerable variability in date palm consumptive water use, both spatially and temporally. The cumulative ETa (CETa) across the six sites ranged from 1299 to 1501 mm with a mean daily ETa of 7.2 mm day−1 in June–July and 1.0 mm day−1 in December at the site with the highest crop water consumption. The mean monthly Ka values varied between 0.63 (December) and 0.90 (June) in the non-salt-affected, sandy loam soil date palms with an average density of 120 plants ha−1 and an average canopy cover and tree height of more than 80% and 11.0 m, respectively. However, the values ranged from 0.62 to 0.75 in a silty clay loam saline-sodic date palm orchard with 55% canopy cover, density of 148 plants ha−1, and 7.3 m tree height. Inverse relationships were derived between the CETa and soil salinity (ECe) in the crop root zone; and between the mean annual Ka and ECe. This information addresses the immediate needs of date growers for irrigation management in the region and enables them to more efficiently utilize water and to achieve full economic gains in a sustainable manner, especially as water resources become less available or more expensive.

Effects of fruit load intensity and irrigation level on fruit quality, water productivity and net profits of date palms

An integrated research coupling a field study with an agronomic-economic model (ANSWER-APP) was conducted to investigate the combined effects of irrigation levels and crop loads on fruit quality, water productivity and profitability of mature date palms. The study took place in Israel’s hyper-arid Arava Valley, where date palm trees are widely cultivated and rely exclusively on brackish water irrigation. Three fruit load intensities (low, FL1; commercial, FL2; high, FL3) and two irrigation levels (W1 and W2, equal to and higher than the local irrigation regime, respectively) were applied in a 22-year-old date palm orchard in 2018–2019. Irrigation amount, fruit quality and yield were measured. Profitability for each treatment was analyzed with the ANSWER-APP. Higher fruit load resulted in higher yield and water productivity, but on the other hand led to reduced fruit physical properties (size and mass), regardless of the irrigation treatment. The improved fruit physical properties and net profits in W2 compared to W1 treatment in each fruit load group resulted from excess salt leaching in the root zone. Notably, trees under W2FL2 treatment were found to have highest net profits. It is concluded that adequate irrigation amounts contribute to net profits in date palm trees treated with high fruit load intensity under saline irrigation conditions.

Influence of pre-harvest foliar spray of fungal culture filtrates on post-harvest biology of date fruit harvested at Khalal stage

Abstract There is a high prevalence of saprophytic fungi in date fruit and date fruit products. Some of these fungi isolated from the infected plants in date palm orchards were identified as Aspergillus niger and Rhizophus oryzae. These fungi cause fruit loss during later stages of maturation and are responsible for severe post-harvest losses of date fruit. They may also deteriorate the overall health of plants. The fungal culture filtrates (FCF) from A. niger (ANFCF) and R. oryzae (ROFCF) were prepared and used as elicitors for the experimentation. These FCFs were foliar sprayed on the date palm plants in the field after the fruit set. Various quality attributes such as weight, firmness and total soluble solids and biochemical properties like total sugars, total proteins, total phenols, ascorbic acid, and antioxidant activity of fresh date fruit (khalal stage) harvested from the FCF treated and untreated plants were studied. The fruit harvested from plants treated with ROFCF showed enhanced levels of total sugar, total proteins, ascorbic acid, and DPPH scavenging activities followed by the fruit from plants treated with ANFCF in comparison to fruit collected from untreated plants. The shelf life of fruit from plants treated with ROFCF and ANFCF increased beyond 14 d at room temperature while the fruit from untreated plants started to deteriorate after 7 d from harvest. The study indicates that the use of fungal culture filtrates as elicitors can help the plant to build up its defense mechanism by elevating the activity of protective enzymes like, Peroxidase (POX), Polyphenol oxidase (PPO) and Phenylalanine ammonia lyase (PAL). It also enhances the growth of plant and improve the quality as well as increases shelf life of fruit.