Khawaja Ghulam Rasool

New Initiatives for Management of Red Palm Weevil Threats to Historical Arabian Date Palms

ABSTRACT The date palm is an important part of the religious, cultural, and economic heritage of the Arabian Peninsula. This heritage is threatened by the recent invasion of the red palm weevil (RPW) from Southeast Asia. In Saudi Arabia, a national campaign for control of RPW by containment/destruction of infested plants, injection and spraying of biochemical and chemical pesticide treatments in heavily infested and newly infested areas, and the use of pheromone/ kairomone traps for monitoring and reduction of RPW populations has been only partially successful in controlling its spread. New methods are needed to help manage the RPW populations. At a workshop in Riyadh in March 2010, plans were recommended to 1) devise and test new biological, chemical, and biotechnological methods to manage RPW in farms and urban palms; 2) compare the economic and logistic feasibility of acoustic and other detection methods against RPW larvae; and 3) develop biosensor indicators of RPW infestation in date palms. If these initiatives are successful, they will be of great assistance to landscape and orchard managers dealing with such a challenging pest of a highly valuable tree.

Identification of Proteins Modulated in the Date Palm Stem Infested with Red Palm Weevil (Rhynchophorus ferrugineus Oliv.) Using Two Dimensional Differential Gel Electrophoresis and Mass Spectrometry

A state of the art proteomic methodology using Matrix Assisted Laser Desorption/Ionization-Time of Flight (MALDI TOF) has been employed to characterize peptides modulated in the date palm stem subsequent to infestation with red palm weevil (RPW). Our analyses revealed 32 differentially expressed peptides associated with RPW infestation in date palm stem. To identify RPW infestation associated peptides (I), artificially wounded plants (W) were used as additional control beside uninfested plants, a conventional control (C). A constant unique pattern of differential expression in infested (I), wounded (W) stem samples compared to control (C) was observed. The upregulated proteins showed relative fold intensity in order of I > W and downregulated spots trend as W > I, a quite interesting pattern. This study also reveals that artificially wounding of date palm stem affects almost the same proteins as infestation; however, relative intensity is quite lower than in infested samples both in up and downregulated spots. All 32 differentially expressed spots were subjected to MALDI-TOF analysis for their identification and we were able to match 21 proteins in the already existing databases. Relatively significant modulated expression pattern of a number of peptides in infested plants predicts the possibility of developing a quick and reliable molecular methodology for detecting plants infested with date palm.

Comparative Efficacy of CO2 and Ozone Gases Against Ephestia cautella (Lepidoptera: Pyralidae) Larvae Under Different Temperature Regimes

Comparative efficacy of three different modified atmospheres: 100% CO2, 75% CO2 + 25% N2, and 22 ppm ozone were examined against larval mortality of the almond moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae) at temperature regimes of 25°C and 35 ± 2°C and 60 ± 5% relative humidity, and 9:15 dark and light. Wandering young larval instars, which are fast growing, large enough in size and considered as more tolerant to modified atmosphere, were collected directly from the rearing culture, placed inside pitted date fruits of vars.: “Khudri,” “Ruziz,” and “Saqie,” were treated with aforementioned gases for 24, 48, and 72 h. The immediate and delayed larval mortality was recorded after each exposure timing. Ozone possessed the strongest fumigant toxicity causing 100% mortality with all varieties, at 25 and 35°C after 24 h exposure and was more effective than 75% CO2 that caused 83 and 100% immediate mortality with variety ruziz at 25 and 35°C, respectively. Extending the treatments exposure time to 72 h, 100% mortality was recorded by exposing larvae to any of the studied gases at 25 and 35°C. These results suggest that gases and temperature used in this study can be effectively used to control E. cautella in dates and stored grains.

Differential Proteomic Analysis of Date Palm Leaves Infested with the Red Palm Weevil (Coleoptera: Curculionidae)

Abstract The red palm weevil, Rhynchophorus ferrugineus (Oliv.) (Coleoptera: Curculionidae), is a highly damaging pest of palm trees worldwide. The infestation is highly concealed in nature. Hence, a highly sensitive and reliable early detection technique needs to be applied in the field for identification and treatment of the infested date palms to curtail further infestation. We have recently reported the differential proteomic analysis of the date palm stem tissues associated with the red palm weevil infestation. In this study, we examine the response of date palm infested with red palm weevil based on the leaf proteome expression changes detected using two-dimensional differential gel electrophoresis (2D-DIGE) followed by Matrix-Assisted Laser Desorption/Ionization-Time-of-Flight (MALDI-TOF). We observed qualitative and quantitative proteome differences between the control and weevil-infested date palm samples. The red palm weevil infestation induced specific responses attributable to weevil feeding, relative to artificially wounded trees (which were used as a control). Differential proteomics led to the identification of 32 red palm weevil infestation-specific protein spots (P ≤ 0.05 having ≥ 1.5-fold modulation) that were further subjected to mass spectrometer analysis for identification and characterization. Proteins involved in plant stress and plant defense, photosynthesis, carbohydrate utilization, and protein degradation were affected in infested plants. The differentially expressed red palm weevil infestation-specific peptides can be used as biomarkers for the identification of early infestation with this insect in date palm trees. Moreover, our study demonstrates the potential use of proteomic strategies in diagnosing phyto-infestation caused by insect pests, diseases, and perhaps even for variety selection.

Evaluation of Natural Additives to Enhance the Persistence of Spodoptera littoralis (Lepidoptera: Noctuidae) Nucleopolyhedrovirus (SpliMNPV) Under Field Conditions in Saudi Arabia

Nucleopolyhedrovirus is an effective biocontrol agent but for its biggest disadvantage of short persistence under sunlight conditions. In this study, 10 plant extracts were evaluated as ultraviolet (UV) protectants to improve the persistence of Spodoptera littoralis multiple-embedded nucleopolyhedrovirus (SpliMNPV) against cotton leafworm (Spodoptera littoralis Boisduval). In the primary lab screening test, 5 out of 10 additives (cloves, henna, green tea, pomegranate, and grape extracts) presented a high rate of virus protection with original activity remaining (OAR) percentage of 100%, 97%, 91%, 90.6%, and 77%, respectively, when used at a concentration of 1% and exposed to UVB for a period of 1 h. A secondary screening was then performed with these best five extracts at a concentration of 0.5% and for an exposure timing of 5 h to UVB. Among these, clove and henna that showed highest protection with OAR values of 96.6% and 76.5%, respectively, were selected for the field trials. When applied on cabbage in the field during sunny summer conditions, clove and henna extracts enhanced the persistence of SpliMNPV by twofold. These findings are encouraging to be applied in the field studies.

Biological Traits of Cadra cautella (Lepidoptera: Pyralidae) Reared on Khodari Date Fruits Under Different Temperature Regimes

Abstract The almond moth, Cadra cautella (Walker) (Lepidoptera: Pyralidae), is a serious worldwide pest of dates and other crops, both in the field and in storage. Infestation by this pest significantly limits the sale and export of dates. Modified atmospheres, the temperature manipulations, are the best eco-friendly alternatives in stored product protection. We examined temperature regulation as an ecologically friendly method of pest management in stored food commodities, in particular, its effects on characteristics of C. cautella biology, including development time, oviposition period, fecundity, fertility, and longevity of adults reared on date cultivar ‘Khodari,’ at temperatures of 15, 25, and 35 ± 1 °C, with 65 ± 5% relative humidity and a photoperiod of 15:9 (L:D) h. Six larval instars were recorded at each temperature. Larval development was sluggish at 15 °C; therefore, daily observations were terminated after 180 d of the larval span for this temperature. Total larval spans of 48.95 ± 0.76 and 32.12 ± 1.08 d were recorded at 25 °C and 35 °C, respectively. A mean ovipositional period of 5.80 ± 0.44 d yielding 213.60 ± 13.41 eggs per female, with hatchability of 85.94 ± 2.97%, was recorded at 25 °C, whereas at 35 °C, a mean ovipositional period of 1.60 ± 0.26 d yielded 19.80 ± 5.11 eggs per female, with no hatchability. These differences were highly significant. Our observations of poor development at 15 °C, lower numbers of eggs and absence of hatchability at 35 °C, together with head capsule measurements and growth ratios, can be of benefit when planning management strategies to reduce C. cautella infestation.