**5.3 Chemical treatments**

Preventive and curative chemical treatments are essential for the efficient management of RPW [27, 63]. Fajardo [64] and Aldawood [65] have described protocols for these treatments in detail.

## *5.3.1 Preventive treatments*

Preventive chemical treatments are often abused and deployed unnecessarily on a calendar basis resulting in drawbacks associated with these treatments, such as pest developing resistance to chemical pesticides, residues of the chemicals in the fruit (dates/coconut) and resurgence of secondary pests and contamination of the environment. Recent reports suggest that RPW is developing resistance to the several insecticides [66, 67]. Overdependence on pesticide application in date plantations has resulted in the residue level of certain insecticides and acaricides being higher than the maximum residue levels permitted in dates [68]. Preventive treatments should only be carried out in farms with high weevil activity as gauged from high infestation and the removal of infested palms/high trap captures/high seasonal activity in the Middle East during March–May and September–October. It is imperative to treat all fresh wounds on palm immediately after the frond and offshoot removal [26, 69–71]. These operations of cleaning the palm could be preferably adopted during the peak winter months when temperatures are low and not conducive for egg hatch and larval development. The commonly used insecticides for preventive treatments are imidacloprid, thiamethoxam, avermectin, abamectin, chlorpyrifos and phosmet. It should be borne in mind that the preventive insecticide treatments are often unnecessary and excessive, which would have negative impact on the environment as a whole.

## *5.3.2 Curative treatments*

The curative insecticidal treatment of RPW-infested palms in the early stage of attack is an integral part of the control strategy. Such palms recover with insecticide

**13**

*Red Palm Weevil* Rhynchophorus ferrugineus *(Coleoptera: Curculionidae): Global Invasion…*

treatment [63, 72, 73]. Ferry [74] provided a detailed protocol of mechanically sanitizing palms in the early stage of attack, while Aldawood [65] presented a comprehensive protocol to inject palms with insecticide in the early stage of attack. Although pressure injectors are used to deliver the insecticide solution to the infested site inside the palm, this technique could damage the palm tissue if the pressure exceeds 2 bar. The diffusion method (gallon method) by cleaning the palm around the infested site on the palm, drilling 4–6 slanting holes 20 cm deep at an angle and pouring insecticide solution into each of the holes is simple, cost-effective and safe. Treat the palm again after 15 days. Once the palm recovers and if the infestation site is close to the ground, cover the treated site with soil to facilitate rooting. For ornamental palms, including ornamental date palms, a new injection technique based on the microinfusion of avermectin insecticide allows to protect the palms at a very low cost over a period of 1 year [75]. Commonly used insecticides for curative treatments are the following: imidacloprid, thiamethoxam, avermectin and abamectin. In organic date plantations, the proven plant origin insecticides would have to be used to treat RPW-infested palms. Several pressure injectors are available in the market which should be used with extreme caution (not >2 bar pressure), to avoid rupture of palm tissue that can lead to death of the treated palm. Ferry and Gomez [63] recommend that only a limited number of stem injections may be carried out in ornamental palms while prohibiting stem injection on a preventive basis in palms

Even in well-managed RPW-IPM programmes, a certain percentage of the infestations detected is in the advanced stage of attack, where such palms exhibit large tissue damage often harbouring adult weevils with overlapping generations of the pest and have to be removed (eradicated). Such palms disperse adult weevils in the field that result in new infestations which reverse the achievements made in controlling the pest. It is of utmost importance to detect infestations before adult weevils emerge and disperse. Al-Shawaf et al. [76] validated an area-wide RPW IPM programme in the Al-Ahsa oasis of Saudi Arabia using palm removal (eradication) data as a criterion to judge the success of the field operations. Palm eradication levels above 20% of the infested palms are not desirable, which reveals that the pest

Vidyasagar [77] outlined a detailed protocol for the safe removal and disposal of

1.Identify the badly infested or damaged palms and mark all such palms with a distinct colour tape or spray paint, or a specific number of straps. Infestation due to RPW could be considered severe in date palms if more than 30% of the

2.Initiate the removal process as soon as possible. Otherwise, the adults from these infested palms will make their way to healthy palms in the vicinity,

3.As a prophylactic measure, soak, drench or shower the palm crown and also

In many countries, shredding machines are used to destroy the severely infested palms at another site, where the severely infested palms are cut into logs and the palm pieces (fronds and trunk) are transported to the shredding site.

the trunk and bole regions with a recommended pesticide.

severely infested palms. The protocol broadly recommends to the following:

*DOI: http://dx.doi.org/10.5772/intechopen.93391*

grown as food crops.

**5.4 Removal of severely infested palms**

is proliferating and control tactics need adjustments.

trunk tissue is damaged at the infestation site.

making the task much more difficult.

*Red Palm Weevil* Rhynchophorus ferrugineus *(Coleoptera: Curculionidae): Global Invasion… DOI: http://dx.doi.org/10.5772/intechopen.93391*

treatment [63, 72, 73]. Ferry [74] provided a detailed protocol of mechanically sanitizing palms in the early stage of attack, while Aldawood [65] presented a comprehensive protocol to inject palms with insecticide in the early stage of attack. Although pressure injectors are used to deliver the insecticide solution to the infested site inside the palm, this technique could damage the palm tissue if the pressure exceeds 2 bar. The diffusion method (gallon method) by cleaning the palm around the infested site on the palm, drilling 4–6 slanting holes 20 cm deep at an angle and pouring insecticide solution into each of the holes is simple, cost-effective and safe. Treat the palm again after 15 days. Once the palm recovers and if the infestation site is close to the ground, cover the treated site with soil to facilitate rooting. For ornamental palms, including ornamental date palms, a new injection technique based on the microinfusion of avermectin insecticide allows to protect the palms at a very low cost over a period of 1 year [75]. Commonly used insecticides for curative treatments are the following: imidacloprid, thiamethoxam, avermectin and abamectin. In organic date plantations, the proven plant origin insecticides would have to be used to treat RPW-infested palms. Several pressure injectors are available in the market which should be used with extreme caution (not >2 bar pressure), to avoid rupture of palm tissue that can lead to death of the treated palm. Ferry and Gomez [63] recommend that only a limited number of stem injections may be carried out in ornamental palms while prohibiting stem injection on a preventive basis in palms grown as food crops.

### **5.4 Removal of severely infested palms**

Even in well-managed RPW-IPM programmes, a certain percentage of the infestations detected is in the advanced stage of attack, where such palms exhibit large tissue damage often harbouring adult weevils with overlapping generations of the pest and have to be removed (eradicated). Such palms disperse adult weevils in the field that result in new infestations which reverse the achievements made in controlling the pest. It is of utmost importance to detect infestations before adult weevils emerge and disperse. Al-Shawaf et al. [76] validated an area-wide RPW IPM programme in the Al-Ahsa oasis of Saudi Arabia using palm removal (eradication) data as a criterion to judge the success of the field operations. Palm eradication levels above 20% of the infested palms are not desirable, which reveals that the pest is proliferating and control tactics need adjustments.

Vidyasagar [77] outlined a detailed protocol for the safe removal and disposal of severely infested palms. The protocol broadly recommends to the following:


In many countries, shredding machines are used to destroy the severely infested palms at another site, where the severely infested palms are cut into logs and the palm pieces (fronds and trunk) are transported to the shredding site.

*Invasive Species - Introduction Pathways, Economic Impact, and Possible Management Options*

weevil captures. It is important to emphasize that poor bait lure synergy due to sub-standard trapping protocols would end up in the palm smelling better than the trap and attracted weevils getting oriented to the palm instead of entering the trap. This is a very dangerous situation where a poorly maintained trap acts as a catalyst

Although the food-baited RPW pheromone trap is most popular, the periodic replacement of the food bait is cumbersome and not sustainable in the long run, especially in area-wide control programmes. In this context, bait and trap free technique of attract and kill has been tested and used to curtail the emerging adult RPW population [59, 60]. Another service-less RPW trapping option that works without the food bait/water is the dry Electrap™ [48]. The cost of incorporating these techniques in an area-wide control programme could be a factor to be considered and needs to be compared with the traditional food-baited pheromone trap before adoption. Large-scale control programmes would stand to benefit if smart traps capable of recording and transmitting weevil capture data on a 24×7 basis are developed. In this context, Potamitis et al. [61] and Aldhryhim and Al-Ayedh [62] have developed and tested smart traps for RPW, but these need advancement for large-scale deployment in the field. An ideal RPW pheromone trap would be the one that does not need servicing and automatically transmits weevil capture data on

Preventive and curative chemical treatments are essential for the efficient management of RPW [27, 63]. Fajardo [64] and Aldawood [65] have described protocols

Preventive chemical treatments are often abused and deployed unnecessarily on a calendar basis resulting in drawbacks associated with these treatments, such as pest developing resistance to chemical pesticides, residues of the chemicals in the fruit (dates/coconut) and resurgence of secondary pests and contamination of the environment. Recent reports suggest that RPW is developing resistance to the several insecticides [66, 67]. Overdependence on pesticide application in date plantations has resulted in the residue level of certain insecticides and acaricides being higher than the maximum residue levels permitted in dates [68]. Preventive treatments should only be carried out in farms with high weevil activity as gauged from high infestation and the removal of infested palms/high trap captures/high seasonal activity in the Middle East during March–May and September–October. It is imperative to treat all fresh wounds on palm immediately after the frond and offshoot removal [26, 69–71]. These operations of cleaning the palm could be preferably adopted during the peak winter months when temperatures are low and not conducive for egg hatch and larval development. The commonly used insecticides for preventive treatments are imidacloprid, thiamethoxam, avermectin, abamectin, chlorpyrifos and phosmet. It should be borne in mind that the preventive insecticide treatments are often unnecessary and excessive, which would have negative

The curative insecticidal treatment of RPW-infested palms in the early stage of attack is an integral part of the control strategy. Such palms recover with insecticide

in creating new infestations.

a 24×7 basis to the operations control unit.

**5.3 Chemical treatments**

for these treatments in detail.

impact on the environment as a whole.

*5.3.2 Curative treatments*

*5.3.1 Preventive treatments*

**12**

Utmost care needs to be taken that there are no escapes of the adult weevils during transportation, for which the palm pieces are to be wrapped in plastic wrapping that is sealed with a tape or transported using enclosed trucks. This is a very expensive process and therefore in-situ (on farm site) removal and disposal of severely infested palm tissue by cutting into small pieces (20 × 10 cm) and soaking with insecticide is recommended [75]. In some countries, the removal of severely infested palms is outsourced to private agencies. Here, bureaucratic procedures in issuing work orders to contractors often result in delay which in turn leads to the spread of the weevil.

Abandoned and neglected plantations also harbour the pest and have to be closely monitored for incidence of RPW by intensive inspection campaigns and installing monitor traps. Farmer cooperation to assist in tackling the pest in neglected gardens should also be sought through persistent awareness programmes. The technique of attract and kill is suited for such plantations. If the plantation is dry with no irrigation and the palm tissue is hard, in all probability, RPW will not prefer such a garden. If there is no pest in an abandoned plantation, these palms should not be removed as palm volatiles emitted during the removal process may attract the pest.

## **5.5 Validating the control programme**

In an area-wide RPW IPM programme, the judicious use of resources (men and material) is vital. Often scarce labour and resources have to be used where most required and the control strategy has to be adjusted by providing resources where most needed. In this context, data on weevil captures in traps, infestation reports and removal of severely infested palms could be used to gauge the situation. Faleiro [26] proposed an assumed action threshold of 1% infestation in large plantations. He developed sequential sampling plans to accurately assess the pest status in coconut and date palm [78, 79] based on infestation reports where in the action threshold, the aggregation index of RPW and the risk of making the wrong decision are built into the plan. The sampling plans are efficient tools in decision-making, particularly at very low and high levels of infestation and can be used to assess the performance of RPW- IPM programmes that are in progress. Al-Shawaf et al. [76] analysed the monthly trap capture data, the infestation reports on the removal of severely infested palms and the above sampling plan [79] to categorize infestation in 15 operational areas (4000 ha) in the Al-Ahsa date palm oasis of Saudi Arabia for a period of 6 months between March and September 2011. They found that the IPM strategy adopted had the desired impact in the East of the oasis, but needed minor adjustments in the centre and called for major reinforcement in the North of the Al-Ahsa oasis. Similarly, Hoddle et al. [80] assessed the impact of pheromone trapping, pesticide applications and eradication of the infested date palms for a period of 5 years between 2007 and 2012, for RPW management in 1104 ha in Al Ghowaybah, of the Al-Ahsa oasis in Saudi Arabia. They concluded that the enhanced RPW management programme that commenced in 2009 had a significant impact against the pest.

GIS-based models can also be developed to validate the strategy at periodic intervals based on trap captures and infestation reports [32, 33]. This helps to judiciously use the resources where most required. FAO has proposed a real-time database and a web portal for the management of RPW at the local, national and NENA region. Furthermore, a mobile app for android and iOS smart phones to record geo-referenced data at the field location on a standard form needs to be developed. FAO has initiated the process to validate the *SusaHamra* app to assist farmers in better monitoring and managing the RPW. A global platform is being

**15**

developed.

*Red Palm Weevil* Rhynchophorus ferrugineus *(Coleoptera: Curculionidae): Global Invasion…*

Over two decades ago, Abraham et al., [27] first highlighted the importance of quarantine treatments to check the spread of RPW through the infested date palm offshoots and recommended to dip the bole of offshoots before transportation in 0.1% chlorpyrophos for 10 min. In Egypt, quarantine and certification programmes recommend zero tolerance for RPW to block the spread of the pest to secondary foci within planted acreage [81]. Later Faleiro [27] proposed to stop movement of planting material from infested plantations within the country and from one country to another. Wherever this was not possible, it was proposed to implement strict pre- and post-entry quarantine regimes, wherein only pest-free and certified planting material can be transported. Besides date palm offshoots transported for farming, the movement of large palms intended for ornamental gardening contributes largely to the spread of this deadly pest [28]. Hence, it is of utmost importance to keep a strict watch on the movement of planting material (offshoots/palms) for both farming and landscape gardening so that only a treated and pest-free material is allowed to be transported within national boundaries [26, 37]. Al-Shawaf et al. [82] recommended to dip date palm offshoots in 0.004% Fipronil for 30 min before transporting to ensure the complete mortality of the hidden larval stages, if any, and complete certification and transport of the treated offshoots to the new planting site within 72 h of treatment. Studies carried out in Spain in *P. canariensis*

the stages of RPW in an infested palm tree, and is recommended as a quarantine protocol provided the dose is not phytotoxic to the treated palms [83]. A sound protocol for the treatment of large palms for ornamental gardening needs to be

Although regulations/decrees to regulate the movement of palms for planting exist in several countries, implementing the decrees in letter and spirit is often lacking [37, 84]. In this context, some European Union (EU) guidelines that could be useful are the following: delimitation of survey and demarcated areas, three monthly official inspections of palm nurseries, annual crop declaration, application of phytosanitary treatments, registration of planting material movement and use of plant passport to monitor the trade of palms. Developing certified palm propagation programmes (certified seed) through tissue culture would go a long way ensuring the propagation of a pest-free material. Recently, Chouibani [11] in the FAO guidelines on RPW management outlined detailed phytosanitary protocols for the movement of palms in context of stopping the spread of RPW within national and international borders and proposed to identify the infested zone where the presence of RPW is confirmed and also a buffer zone extending at least 10 km beyond the boundary of the infested zone. A strict vigil is to be maintained on the movement of palms and plant nurseries within the demarcated area. The demarcated area will be declared free from RPW if, during the three consecutive years, RPW has not been detected. Chouibani [11] further recommends that ornamental palm trees originating from recognized nurseries should be imported. Nurseries should be authorized, certified, mapped and regularly inspected by the NPPO of the exporting country.

for 3 days is enough to kill all

established for mapping field data and analytics for better decision-making. Furthermore, remote sensing is being combined with artificial intelligence to map palm trees for the improved monitoring of RPW spread at both the regional and global levels ([34, 35]; http://www.fao.org/news/story/en/item/1184673/icode/). At *level-2*, the RPW-IPM strategy is to be supported by a robust plant quaran-

*DOI: http://dx.doi.org/10.5772/intechopen.93391*

tine/phytosanitation regime.

**5.6 Quarantine/phytosanitation**

suggest that a dose of 1.14 g aluminum phosphide/m3

*Red Palm Weevil* Rhynchophorus ferrugineus *(Coleoptera: Curculionidae): Global Invasion… DOI: http://dx.doi.org/10.5772/intechopen.93391*

established for mapping field data and analytics for better decision-making. Furthermore, remote sensing is being combined with artificial intelligence to map palm trees for the improved monitoring of RPW spread at both the regional and global levels ([34, 35]; http://www.fao.org/news/story/en/item/1184673/icode/).

At *level-2*, the RPW-IPM strategy is to be supported by a robust plant quarantine/phytosanitation regime.

#### **5.6 Quarantine/phytosanitation**

*Invasive Species - Introduction Pathways, Economic Impact, and Possible Management Options*

spread of the weevil.

**5.5 Validating the control programme**

Utmost care needs to be taken that there are no escapes of the adult weevils during transportation, for which the palm pieces are to be wrapped in plastic wrapping that is sealed with a tape or transported using enclosed trucks. This is a very expensive process and therefore in-situ (on farm site) removal and disposal of severely infested palm tissue by cutting into small pieces (20 × 10 cm) and soaking with insecticide is recommended [75]. In some countries, the removal of severely infested palms is outsourced to private agencies. Here, bureaucratic procedures in issuing work orders to contractors often result in delay which in turn leads to the

Abandoned and neglected plantations also harbour the pest and have to be closely monitored for incidence of RPW by intensive inspection campaigns and installing monitor traps. Farmer cooperation to assist in tackling the pest in neglected gardens should also be sought through persistent awareness programmes. The technique of attract and kill is suited for such plantations. If the plantation is dry with no irrigation and the palm tissue is hard, in all probability, RPW will not prefer such a garden. If there is no pest in an abandoned plantation, these palms should not be removed as

In an area-wide RPW IPM programme, the judicious use of resources (men and material) is vital. Often scarce labour and resources have to be used where most required and the control strategy has to be adjusted by providing resources where most needed. In this context, data on weevil captures in traps, infestation reports and removal of severely infested palms could be used to gauge the situation. Faleiro [26] proposed an assumed action threshold of 1% infestation in large plantations. He developed sequential sampling plans to accurately assess the pest status in coconut and date palm [78, 79] based on infestation reports where in the action threshold, the aggregation index of RPW and the risk of making the wrong decision are built into the plan. The sampling plans are efficient tools in decision-making, particularly at very low and high levels of infestation and can be used to assess the performance of RPW- IPM programmes that are in progress. Al-Shawaf et al. [76] analysed the monthly trap capture data, the infestation reports on the removal of severely infested palms and the above sampling plan [79] to categorize infestation in 15 operational areas (4000 ha) in the Al-Ahsa date palm oasis of Saudi Arabia for a period of 6 months between March and September 2011. They found that the IPM strategy adopted had the desired impact in the East of the oasis, but needed minor adjustments in the centre and called for major reinforcement in the North of the Al-Ahsa oasis. Similarly, Hoddle et al. [80] assessed the impact of pheromone trapping, pesticide applications and eradication of the infested date palms for a period of 5 years between 2007 and 2012, for RPW management in 1104 ha in Al Ghowaybah, of the Al-Ahsa oasis in Saudi Arabia. They concluded that the enhanced RPW management programme that commenced in 2009 had a significant

GIS-based models can also be developed to validate the strategy at periodic intervals based on trap captures and infestation reports [32, 33]. This helps to judiciously use the resources where most required. FAO has proposed a real-time database and a web portal for the management of RPW at the local, national and NENA region. Furthermore, a mobile app for android and iOS smart phones to record geo-referenced data at the field location on a standard form needs to be developed. FAO has initiated the process to validate the *SusaHamra* app to assist farmers in better monitoring and managing the RPW. A global platform is being

palm volatiles emitted during the removal process may attract the pest.

**14**

impact against the pest.

Over two decades ago, Abraham et al., [27] first highlighted the importance of quarantine treatments to check the spread of RPW through the infested date palm offshoots and recommended to dip the bole of offshoots before transportation in 0.1% chlorpyrophos for 10 min. In Egypt, quarantine and certification programmes recommend zero tolerance for RPW to block the spread of the pest to secondary foci within planted acreage [81]. Later Faleiro [27] proposed to stop movement of planting material from infested plantations within the country and from one country to another. Wherever this was not possible, it was proposed to implement strict pre- and post-entry quarantine regimes, wherein only pest-free and certified planting material can be transported. Besides date palm offshoots transported for farming, the movement of large palms intended for ornamental gardening contributes largely to the spread of this deadly pest [28]. Hence, it is of utmost importance to keep a strict watch on the movement of planting material (offshoots/palms) for both farming and landscape gardening so that only a treated and pest-free material is allowed to be transported within national boundaries [26, 37]. Al-Shawaf et al. [82] recommended to dip date palm offshoots in 0.004% Fipronil for 30 min before transporting to ensure the complete mortality of the hidden larval stages, if any, and complete certification and transport of the treated offshoots to the new planting site within 72 h of treatment. Studies carried out in Spain in *P. canariensis* suggest that a dose of 1.14 g aluminum phosphide/m3 for 3 days is enough to kill all the stages of RPW in an infested palm tree, and is recommended as a quarantine protocol provided the dose is not phytotoxic to the treated palms [83]. A sound protocol for the treatment of large palms for ornamental gardening needs to be developed.

Although regulations/decrees to regulate the movement of palms for planting exist in several countries, implementing the decrees in letter and spirit is often lacking [37, 84]. In this context, some European Union (EU) guidelines that could be useful are the following: delimitation of survey and demarcated areas, three monthly official inspections of palm nurseries, annual crop declaration, application of phytosanitary treatments, registration of planting material movement and use of plant passport to monitor the trade of palms. Developing certified palm propagation programmes (certified seed) through tissue culture would go a long way ensuring the propagation of a pest-free material. Recently, Chouibani [11] in the FAO guidelines on RPW management outlined detailed phytosanitary protocols for the movement of palms in context of stopping the spread of RPW within national and international borders and proposed to identify the infested zone where the presence of RPW is confirmed and also a buffer zone extending at least 10 km beyond the boundary of the infested zone. A strict vigil is to be maintained on the movement of palms and plant nurseries within the demarcated area. The demarcated area will be declared free from RPW if, during the three consecutive years, RPW has not been detected. Chouibani [11] further recommends that ornamental palm trees originating from recognized nurseries should be imported. Nurseries should be authorized, certified, mapped and regularly inspected by the NPPO of the exporting country.

### *Invasive Species - Introduction Pathways, Economic Impact, and Possible Management Options*

As regards date palm, only those propagated in vitro in test tubes by laboratories that are officially certified to propagate such materials should be imported.

The RPW-IPM strategy at *level-3* outlines the prospect of palm tolerance to RPW and encourages the use of biological control to combat the pest, besides emphasizing the importance of adopting good agronomic practices.

### **5.7 Palm resistance to RPW**

In perineal crops, such as palms, farmers prefer to cultivate commercial cultivars that are well established and popular in the area/region. These cultivars/ varieties are often the most susceptible to RPW. Host plant resistance has not been fully studied and exploited with regard to RPW in spite of some preliminary research that has characterized palm cultivars in terms of tolerance/susceptibility to RPW [20, 85, 86]. The screening techniques to identify resistant RPW cultivars and parental material for use in breeding programmes need to be developed. The molecular markers-assisted breeding programme for the development of RPW resistant cultivars is another avenue that could be pursued. Advanced molecular techniques such as RNAi could hasten the utilization of host plant resistance against RPW [70].

#### **5.8 Agro-techniques and RPW management**

Palm density, irrigation methods and protection of tissue immediately after the frond and offshoot removal are probably the most important agro-techniques related to RPW management [87–89].

#### *5.8.1 Palm density*

Traditional date palm plantations have palms planted at a close spacing, often restricting sunlight penetration resulting in the build up of in-groove humidity conducive for the development of RPW [90]. Dense planting coupled with flood irrigation and inadequate drainage accelerates the build up of in-groove humidity. In this context, it is recommended to plant new plantations at the recommended spacing to allow sunlight penetration.

#### *5.8.2 Impact of irrigation*

In flood-irrigated palms, often, the water touches the trunk at the ground, which encourages adult weevils to oviposit in the collar region of such palms, resulting in new infestations. It is therefore recommended that drip irrigation systems be installed as a precaution for RPW control [87]. Care should be taken to see that palms receive adequate irrigation water as the scarcity of water may result in the incidence of the date palm stem borer *Jebusaea hammerschmidti* [91].

#### *5.8.3 Protecting fresh wounds*

Adult weevils are attracted to palm volatiles emitted from the fresh wounds of palm tissue after the frond and offshoot removal. This calls for the immediate treatment of wounds on the palm to mask the emitting palm volatiles and avoid the gravid female weevil getting attracted to these sites for oviposition. As a precaution, these pruning activities could be carried out during winter when temperatures are low which adversely impacts the egg hatch and larval development [22]. No oviposition was observed for females kept below 15°C [92].

**17**

**Figure 7.**

*Red Palm Weevil* Rhynchophorus ferrugineus *(Coleoptera: Curculionidae): Global Invasion…*

Biological control is an integral part of several sustainable IPM programmes the world over. Biocontrol could play a significant role in augmenting the existing pheromone-based RPW-IPM strategy. Conventional control measures against RPW such as mass pheromone trapping and chemical treatments for preventive and curative purposes have not given the desired level of control. A wide range of RPW natural enemies, viz. insects, bacteria, fungi, viruses, yeasts, entomopathogenic nematodes (EPN) and birds have been reported from several countries [26, 93]. Mazza et al. [94] enlisted more than 50 biological control agents against the *Rhynchophorus* group of weevils. Al-Deeb et al. [95] reported the presence of phoretic mites of the genera *Uropoda*, *Uroobovella* and *Curculanoetus* on RPW in UAE. Whether these mites cause a pathological effect on the weevil need to be investigated. In this respect, it has been found that an unidentified species of phoretic mite could cause high mortality among RPW pupae, as well as attenuation of adult weevils (El-Shafie, unpublished data) (**Figure 7**). Yasin et al. [96] reviewed the potential role of potential microbial agents in the control of RPW and concluded that strains of the fungi *Beauveria bassiana* and *Metarhizium anisoplia*e, isolated from naturally infected RPW, could contribute to biological control of this pest. There are several publications to show the efficacy of entomopathogenic nematodes (EPN) and the entomopathogenic fungi (EPF) in the laboratory and semi-field assays [96–101]. Laboratory and semi-field cage studies showed the possibility of infecting RPW adults with *B. bassiana* using pheromone traps [100]. Reports from Spain suggest that the EPN, *Steinernema* sp. [99], and the EPF, *B. bassiana* [102], are promising in the field. The role of parasitic tachinid flies from South America against the *Rhynchophorus* group of weevils could also be another potential avenue to explore [103, 104]. The current RPW-IPM programme could be significantly strengthened if the known biological control agents could be delivered to the target site and also

At *level-4*, the strategy mainly visualizes capacity building, robust extension programmes to sensitize all stakeholders and farmer participation in the control

*Unidentified phoretic mite on RPW adult (left) and pupa (right) (Photo: Hamadttu A. F. El-Shafie).*

*DOI: http://dx.doi.org/10.5772/intechopen.93391*

**5.9 Biological control**

sustained in the field.

programme.

*Red Palm Weevil* Rhynchophorus ferrugineus *(Coleoptera: Curculionidae): Global Invasion… DOI: http://dx.doi.org/10.5772/intechopen.93391*
