Identification, distribution, management and quarantine issues of invasive pests
- Part 2 -

AN Shylesha *

Western flower thrips, Frankliniellaoccidentalis (Pergande)

The western flower thrips (Frankliniellaoccidentalis (Pergande) is an important pest insect in agriculture. This species of thrips is native to North aerica but has spread to other continents including Europe, Australia, and South America via transport of infested plant material.

It has ben documented to feed upon over 500 different species of host plants, including a large number of fruit, vegetabl, and ornamental crops. The adult male is about 1 mm long/ the female is slightly larger, about 1.4 mm. Most western flower thrips are female and reproduce by arrhenotokous parthenogenesis. Males are rare. They are variable in color, with some color types more abundant in certain sesons.

Various species of the worldwide anthocorid bug Orius are used in biological control against thrips and these bugs are evidently important as predators in many natural populations. A majority of natural enemy records for F. occidentalis are from greenhouses. Neoseiuluscucumeris is one of the most widespread mites used in attempts at the biological control.

Control with hymenopterous parsites seems to have been less effective, although the polyphagous eulophid, Ceranisusmenes, has been used in severa countries with varying levels of success (Loomans et al., 1995). Fungal pathogens like Metarhiziumanisopliae and nematodes, such as Steinernemafeltiae are also being used commercially.

Eucalyptus gall wasp, Leptocybeinvasa

Leptocybeinvasa apparently originated from Australia is a pest in several countries in Mediterranean, Africa and Asia. Its occurrence was recorded in 2004 at Tamil Nadu, which was subsequently found in several locations in Tamil Nadu, Karnataka, Andhra Pradesh and Uttar Pradesh in 2007.

The introduced natural enemies that feed on leaves, flowers and berries have slowed down the spread of this weed. There is room for the introduction of an increased number of natural enemies to suppress this weed in India (Muniappan and Viraktamath, 1993).

Aceriaguerreronis Keifer

The coconut mite, Aceriagurreronis, was first reported in Kerala and now is a national pest causing extensive damage to coconut. The mite inhabits the tender nuts especially below the perianth and the button size is most crucial for attack. A number of natural enemies such as Amblyseius Largoensis and Hirsutellathompsonii have been reported to attack this pest, none of them were effective in reducing the populations.

Recently, Fernando et al. (2010) reported that the release of 10,000 mites of Neoseiulusbraka resulted in the significant increase in the predatory mite population of coconut in Sri Lanka with significant decrease in the populations of a. guerreronis.

Erythrina gall wasp, Quadrastichuserythrinae Kim.

This wasp was first reported on the Erythrina spp. in major black pepper areas of Kerala and Karnataka in 2006. Later, this was observed in several states like Maharashtra and Karnataka.

The infestation by this species on Erythrina was found to be a major constraint for the growth and production of black pepper vines in recent years. An eulophid parasitoid, Aprostocetusexertus was the potential of being used as biocontrol agent against Q. erythrinae (La Salle, 2009).

The Fall Armyworm (FAW)

The Fall Armyworm (FAW) was first confirmed outside of its native Americans in Africa in early 2016. Since then it has rapidly spread across Sub-Saharan Africa, infesting tens of millions of hectares of maize, sorghum and millet. In mid-2018 FAW was confirmed in Yemen and India and now continues to spread quickly.

Late 2018 there were reports about infestations in Sri Lanka and Bangladesh (official confirmation ongoing), and in mid-January some (unconfirmed) reports of FAW presence in Thailand and Myanmar. FAW can cause significant yield loss to maize and other if not managed well or in the absence of natural control.

Augmentative release of Trichogramma Pretiosum @ 50,000 or Telenomus Remus @ 10,000 adults acre-1 at weekly intervals or based on trap catch of 3 moths trap-1.

Application of Metarhiziumanisopliae talc formulation (1 x 108cfu g-1) @ 3 g l-1 whorl application at 15-25 days after sowing. Another 1-2 sprays may also be given at an interval of 10 days depending on pest damage. Bacillus thuringiensis v. kurstaki formulations viz., Dipel 8 l@ 2 ml 1-1 of water or Delfin 5WG @ 2 gl-1 water.

CONCLUSION

Most of the invasive have occurred through the human activities and with the opening of World trade, and the frequent movement of travellers between countries it becomes imperative to take strict quarantine measures for avoiding the threats.

Larger consignment importation is being monitored with appropriate quarantine measures; materials especially planting materials and cut flowers taken by the international travel passengers often miss the quarantine procedures, facilitating the paths for the introduction of the invasive.

This becomes more crucial in cases where the travel is between very close nations of the same climatic region. The containers and planting materials often pose a threat for the invasive, especially for the bore pests since these containers were not subjected to regular quarantine procedure.

It becomes imperative for the exporting countries to properly disinfect the packing materials before being used. A group of researchers, including entomologists, pathologists, botanists and quarantine officials should form a network for the early detection of the invasive so that precious time between the interception and the possible escape is avoided. More important is the involvement of biosystematics that can identify the pests correctly to the species level.

Training and refresher courses on biosystematics are necessary for quarantine officials to refresh their knowledge on the biosystematics. Use of molecular tools is also very essential for the easy identification of the invasive species.

A checklist of the possible invasive and their natural enemies has been prepared and given to the National Biodiversity Authority along with the international agreements for the import of the effective biological control agents for classical biological control.

A network on the invasive species may be developed or the existing invasive network may be a strength end for sharing valuable information at the earliest. Frequent seminars and international workshops may be conducted for the identification of the possible invasive and their management.

For further details contact: -
Public Relations & Media Management Cell,
CAU, Imphal.
Email: [email protected]

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