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Plantwise Technical Factsheet

melon thrips (Thrips palmi)

Host plants / species affected
Allium cepa (onion)
Capsicum (peppers)
Capsicum annuum (bell pepper)
Chrysanthemum (daisy)
Citrullus lanatus (watermelon)
Cucumis melo (melon)
Cucumis sativus (cucumber)
Cucurbita moschata (pumpkin)
Cucurbita pepo (marrow)
Cucurbitaceae (cucurbits)
Fabaceae (leguminous plants)
Glycine max (soyabean)
Gossypium (cotton)
Helianthus annuus (sunflower)
Lactuca sativa (lettuce)
Mangifera indica (mango)
Nicotiana tabacum (tobacco)
Orchidaceae (orchids)
Oryza sativa (rice)
Persea americana (avocado)
Phaseolus (beans)
Phaseolus vulgaris (common bean)
Sesamum indicum (sesame)
Solanum lycopersicum (tomato)
Solanum melongena (aubergine)
Solanum tuberosum (potato)
Vigna unguiculata (cowpea)
List of symptoms/signs
Fruit  -  abnormal shape
Growing point  -  dead heart
Growing point  -  external feeding
Leaves  -  abnormal colours
Leaves  -  external feeding
Damage by T. palmi is not unlike that caused by many other species of thrips; when populations are high, their feeding causes a silvery or bronzed appearance on the surface of the plant, especially on the midrib and veins of leaves and on the surface of fruit. Leaves and terminal shoots become stunted and fruit is scarred and deformed. Damaged leaves generally show a darkened, glossy, pearly appearance (Bournier, 1987). Johnson (1986) described heavy damage to watermelon foliage as bronzing and total destruction of the vine tips.

Bournier (1983, 1987) described damage to cultivated cotton caused by T. palmi and, among the symptoms, observed that the oldest tissue may thicken, warp and finally crackle. Damage to cotton seedlings by T. palmi has also been reported in Thailand by Wangboonkong (1981) if there are long periods of drought early in the season.

Apart from Karny (1925), who described T. palmi and observed that it infested both mature and seedling tobacco in Sumatra, one of the earliest reports of damage by T. palmi was Ananthakrishnan (1955). He described the damage to Sesamum plants in Madras, India, as malformation of the stamens, injury to the ovarian wall and the development of a dark pigment on the fruit wall, instead of the usual green colour.

Damage has been described by Nakazawa (1981) in Japan as yellowing of the leaves, topping, scratches on the fruits, malformation of the fruits, poor fruiting and death of the whole plant when populations are high. In Martinique, Denoyes et al. (1986) described the damage on the leaves of aubergine, cucumber, melon and other cucurbits. Pantoja et al. (1988) reported severe damage to cucurbits and solanaceous commercial plantings in 1986 in Puerto Rico, where adult and immature thrips fed gregariously on leaves, stems, flowers and developing fruits. Pepper plants became stunted with a bronzed appearance and aubergine plants showed premature fall of developing fruits and buds, and deformed fruits.

Kawai (1986b) studied the relationship between the density of T. palmi and the damage to Capsicum annuum and aubergine in Japan. He also studied the relationship between different densities of T. palmi and injury to cucumbers grown in a vinyl house (Kawai, 1986c). The growth of cucumber plants was retarded when thrip numbers were high. The tolerable pest densities were estimated at 5.3 adults per leaf for the total fruit yield and 4.4 adults per leaf for the yield of uninjured fruit (assuming an acceptable yield loss of 5% of the maximum yield).

Sakimura et al. (1986) observed that both adults and larvae of T. palmi feed gregariously on leaves, firstly along the midribs and veins. Stems are attacked, particularly at or near the growing tip, and are found amongst the petals and developing ovaries in flowers and on the surface of fruit. They leave numerous scars and deformities, and finally kill the entire plant.
Prevention and control

Chemical Control

Chemical control has given a measure of protection in many countries, for example, on cucurbits in New Caledonia (Guterierrez, 1981) and on watermelon in Hawaii (Johnson, 1986). Nine insecticides were tested against T. palmi on potato in Mauritius, but none gave satisfactory results (Anon, 1987b). Seal et al. (1994) tested the effectiveness of five insecticides for the control of T. palmi on Phaseolus vulgaris, Cucurbita pepo and aubergine in Florida during 1993. Some insecticide screening has also been recorded from South America. In Brazil, Cermeli et al. (1993) tested 11 insecticides and observed a high level of tolerance to chemical control. Flufenoxuron, imidacloprid and chlorfluazuron were the most effective insecticides; however, no insecticide was more than 81.5% effective.

Nishino (1987) studied seasonal fluctuations of susceptibility to insecticides in Japan. Nagai et al. (1981) investigated the effect of paired insecticide mixtures, and Nishino et al. (1982) reported on the effects of certain insecticides on the control of T. palmi. Yoshihara et al. (1984) provided a method of evaluating the susceptibility of T. palmi to several insecticides. Morishita and Azuma (1989) noted that population densities changed in response to pesticide applications in fields of aubergine. Nemoto (1995) evaluated the side effects after aubergine plants were continuously sprayed with the insecticides permethrin, milbemectin, phenthoate and imidacloprid in Japan. The effects on populations of pests and their natural enemies were assessed and revealed the importance of natural enemies such as Orius species. Imidacloprid, which was highly effective against Hemiptera and T. palmi, caused a resurgence of Tetranychus kanzawai. Milbemectin, which had a minimal adverse effect on Orius spp., when used in combination with imidacloprid, maximized the latter's advantages while minimizing its disadvantages. A new insecticidal and acaricidal compound, PF1018, has been reported by Gomi et al. (1994). Application by leaf dipping caused 96% mortality to second-instar larvae of T. palmi.

Nakazawa (1981) reported that T. palmi was not susceptible to acephate, phenthoate or fenitrothion and that no insecticides were practical for use against T. palmi, but by 1992 fenobucarb was being used.

In Taiwan, Su et al. (1985) found that deltamethrin and cypermethrin were effective in controlling T. palmi on aubergine, and Huang (1989) reported that pesticides were most effective if sprayed in the morning or evening. In Hong Kong, Riddell-Swan (1988) highlighted the fact that T. palmi had become resistant to almost all organophosphates.

Etienne et al. (1990) discovered that populations of T. palmi on aubergine in Guadeloupe were much higher in diazinon- and profenofos-treated plots than untreated plots; this was attributed to reduced predator activity in the treated plots. Denoyes et al. (1986) commented that in Martinique, where T. palmi had been discovered in 1985, no chemical control measures had so far been successful, but by 1989, Bon and Rhino reported that profenofos and abamectin were effective.

On Guam, Schreiner (1991) noted that there was no significant effect on the yield of cucumbers in the field, with up to 80 T. palmi per leaf after treatments with carbaryl, dimethoate and Bacillus thuringiensis.

Insect Growth Regulators

The effects of the juvenile hormone mimic pyriproxyfen on T. palmi were evaluated by Nagai (1990c); no difference in mortality was found between those reared on treated or untreated leaves. However, during the pupal stage mortality rose to 70% compared with 30% on untreated leaves. There was no difference in the hatchability of Orius sp. in the laboratory when treated with pyriproxyfen. In the greenhouse, populations of Orius sp. were reduced to very low levels within 10 days of application of carbaryl alone and in combination with pyriproxyfen, but its population density was the same as that on untreated plants when pyriproxyfen was applied on its own.

Nagai et al. (1988b) showed that flufenoxuron inhibited the ecdysis of first-instar nymphs and metamorphosis of second-instar nymphs to pupae, but did not affect the survival rate and fecundity of females. The effect of flufenoxuron on populations on aubergine in the field in Japan was examined in September and October, when suppression of the population by flufenoxuron was slower than by sulprofos.

The activity of five chitin-synthesis inhibitors against T. palmi infesting melon in Japan was evaluated in the laboratory and greenhouse. Diflubenzuron, teflubenzuron, chlorfluazuron, flufenoxuron and chiromazine were tested in the laboratory. The number of larvae which dropped from leaves in order to pupate decreased significantly, and only larvae treated with chiromazine pupated. In the greenhouse, chlorfluzuron and flufenoxuron controlled T. palmi more effectively than diflubenzuron and conventional sprays of fenobucarb (Kubota, 1989).

Integrated Pest Management

Hirose (1991) stressed the importance of considering biological control for T. palmi and also suggested that the resurgence of this pest in South-East Asia during the last 10 years was due to the elimination of its natural enemies by repeated insecticide applications. The effect of insecticides on Orius sp. was investigated by Nagai (1990b) in Japan. Eggs were treated by dipping and results showed that chinomethionate, bromopropylate, pirimicarb and phosalone showed low toxicity. However, carbaryl, a mixture of malathion and fenobucarb, phenthoate and fenthion showed high toxicity to the eggs. Orius apparently showed no susceptibility to buprofezin or bromopropylate when aubergines were sprayed in the field for control of T. palmi, but phosalone, chlorfluazuron and flufenoxuron were highly toxic to Orius species. Nagai (1990a) used fenthion as a control measure when evaluating the effects of predation by Orius. Further evaluation was presented by Nagai (1991a, 1992).

Kawai and Kitamura (1987) concluded that control of T. palmi using insecticides alone was difficult because of the need for the safe use of agricultural chemicals, and they suggested that an integrated control system should be established. A population model of T. palmi was constructed to evaluate the effectiveness of various control methods and to develop an effective control system for T. palmi on cucumber cultivated in a plastic greenhouse.

Kawai and Kitamura (1987) evaluated various control measures on cucumber in plastic greenhouses in Japan and recommended an integrated pest management system. Integrated control of T. palmi on cucurbits in the field in Japan is discussed by Suzuki et al. (1986). An integrated pest management system has already been implemented in Martinique and Guadeloupe (Denoyes et al., 1986).

A pest management strategy was suggested by Hata et al. (1991) in Hawaii to separate susceptible cultivars from preferred cultivars of Dendrobium and the wild bamboo orchid Arundina graminifolia on which T. palmi feeds. Cooper (1991a) provides recommendations for the integrated control of T. palmi in vegetables in Trinidad and Tobago. IPM is probably the most important strategy for dealing with T. palmi, particularly in view of the recognition in Taiwan that frequent insecticidal treatments can lead to increased populations.

Post-Harvest Treatment

There have been few reported efforts directed towards post-harvest treatments to eliminate T. palmi from plant material. Jacqua and Etienne (1987) dipped aubergine fruit in water at various temperatures after harvest to eliminate T. palmi under the calyx. Dipping at 45°C was better for subsequent fruit conservation, as treatment at 50°C could induce fruit damage.

Mann et al. (1995) evaluated post-harvest treatments to control T. palmi on Dendrobium orchid blossoms in Hawaii, including insecticidal dips, isopropyl alcohol dips, insecticidal fogs and hot-water immersion. The limiting factor for all post-harvest treatments was phytotoxicity, characterized by a loss of vase life that differed among cultivars. Insecticidal dips and insecticidal fogs were less phytotoxic than hot-water immersion and isopropyl alcohol dips. Hata et al. (1993) also experimented with insecticidal dips in Hawaii. Double dips applied after harvest reduced >95% of a mixed infestation of Frankliniella occidentalis (90%) and T. palmi (10%) infesting Dendrobium 'Uniwai Princess' blossoms, compared with untreated controls. Single insecticidal dips were not as effective.

Feeding Deterrents

Although Yasuda and Momonoki (1988) noted that a variety of aubergine resistant to T. palmi has been introduced from South-East Asia into Japan, the majority of research on feeding deterrents has been conducted on tomatoes. The effect of tomato leaf constituents on the survival of T. palmi was described by Yasumi et al. (1991). Adult females survived for a long period on a filter paper disc soaked in a 3% aqueous sucrose solution, even if the sucrose-impregnated disc had methanol extracts of cucumber or aubergine leaves applied to it. However, when methanol extract of tomato leaves was applied to the sucrose-impregnated disc, all of the the insects died within a few days. It was concluded that the active substance was an antifeedant rather than a toxin.

Athough T. palmi is polyphagous, Hirano et al. (1994) stated that it does not attack tomatoes in Japan. A crystalline compound possessing strong antifeedant activity was isolated from tomato leaves and was identified as the steroidal glycoalkaloid alpha-tomatine. It was concluded that the immunity of tomato plants to T. palmi is explained solely by the occurrence of alpha-tomatine, because T. palmi does not use airborne information (attractants/repellents) to avoid tomato leaves, and tomato leaves apparently provide the required phagostimulants and nutrients.

Short-distance walking responses of T. palmi to non-preferred tomato and preferred aubergine leaves have been examined by Hirano et al. (1993). In leaf-disc assays, adult females of T. palmi moved randomly and there was neither an oriented approach towards aubergine leaves nor an active avoidance of tomato leaves. Similar results were obtained on leaf-extract-treated filter paper discs. It was concluded that T. palmi is not deterred from tomato during the period from searching to initial settlement; this is supported by a report by Cermeli and Montagne (1993) who observed that, although T. palmi was collected on tomato crops, it did not cause economic damage.

Biological control

Anthocorid bugs play the most significant role in the natural control of T. palmi in many areas where it is a pest. Seven species have been mentioned in the literature: Orius sp. in Japan; O. similis and O. tantillus in the Philippines; O. sauteri in Taiwan; O. maxidentex and Carayonocoris indicus in India; O. insidiosus in Hawaii, USA; and Bilia sp., O. minutus, Wollastoniella parvicuneis and W. rotunda in Thailand. Most of these investigations have been conducted in Japan and, in most cases, the species used has not been identified and is referred to only as Orius sp. Until the identification of the species is settled, it is difficult to make comparisons or suggest other species which might be considered in biological control projects.

The biology of Orius sp. from Japan has been studied by Nagai (1989), who determined the duration of the egg and larval stages in the laboratory. Using T. palmi as prey, the author found that the duration of the stages decreased with an increase in temperature. The predatory effect of Orius sp. on the density of T. palmi was investigated on potted aubergine in a screenhouse (Nagai et al., 1988a) and on aubergine in the field (Kawamoto and Kawai, 1988; Nagai, 1990a). It was concluded that the introduction of Orius sp. lowered the population density of T. palmi on aubergine. Conversely, the population densities of T. palmi, Tetranychus kanzawai and Tetranychus urticae were greater when populations of Orius had been eliminated by insecticides (Kawai and Kawamoto, 1994). Orius spp. were active from May until November, with two population peaks in July-August and in September.

The dispersal of Orius spp. was evaluated by Kawai (1995) on greenhouse-grown aubergine infested with T. palmi. The population density of T. palmi decreased on nine plants adjacent to the plant where the predator was released within a few days after release, and remained low until the end of the examination. Although individuals of Orius spp. dispersed to other parts of the greenhouse afterwards, they could not control the population density of T. palmi effectively, due to the delay in their arrival. It took about 1 month for Orius spp. individuals to disperse to the other end of the greenhouse. It was concluded that the dispersal ability of early-instar nymphs is low while that of late-instar nymphs and adults is high.

Kawamoto and Kawai (1988) observed the effect of Orius sp. on populations of arthropod pests on aubergine in the field in Japan in 1987 and noted that populations of Orius sp. were lower in insecticide-treated plots than in untreated plots. They also noted that populations of T. palmi (together with Tetranychus kanzawai) were higher in treated plots, and suggested that Orius sp. was effective in reducing populations of arthropod pests on aubergine.

In China, Wei et al. (1984) studied the biology and predatory behaviour of O. similis. They found that in the laboratory, one individual of O. similis could prey on ca 440 individuals of T. palmi during its lifetime (both as a nymph and adult). Nagai (1991b) also studied Orius under laboratory conditions in Japan and noted that at 25°C, one average adult female of Orius sp. preyed on 22 second-instar larvae or 26 adults of T. palmi in 24 hours. However, it was further noted that Orius adults did not eat the eggs of T. palmi.

O. tantillus was studied in the laboratory in the Philippines by Mituda and Calilung (1989). The duration of the egg stage averaged 4.52 days and the total life cycle was 14.76 days for males and 16.52 for females. Adult Orius sp. consumed up to 20 thrips per day and the total number killed throughout the predators' lifetime averaged 205.71 for males and 228.10 for females. It was noted that laboratory studies have demonstrated the great potential of the anthocorid as a biological control agent against T. palmi. Six weed species and five crop plants have been recorded as host plants for O. tantillus in the field. Bernardo (1991) lists numerous predators that have been found associated with T. palmi in the Philippines.

The predatory mites Amblyseius mckenziei and A. okinawanus, and Orius sp., were investigated by Kajita (1986) in Japan. Their prey stage preference, prey consumption and feeding behaviour was studied in detail. Adult females of the two species of mites preferred first-instar larvae as prey to second-instar larvae and adult thrips, whereas the numbers of first- and second-instar larvae consumed by second-instar Orius sp. did not differ greatly. Orius sp. did not differ significantly in the number of prey consumed from the two species of mites.

Kumar and Ananthakrishnan (1984) studied the anthocorids O. maxidentex and Carayonocoris indicus in the laboratory and in the field near Madras, India. O. maxidentex fed on T. palmi on the young foliage of sesame and, after the crop was harvested, was abundant on the weed Croton sparsiflorus, preying on T. palmi until prey populations died out in September.

In Trinidad the only predator discovered was the coccinellid beetle Coleomegilla maculata (Cooper, 1991b). In Hawaii, Mau et al. (1989) recorded O. insidiosus and Franklinothrips vespiformis as predators of T. palmi, and in Taiwan, Wang (1994) evaluated the mirid bug Campylomma chinensis and O. sauteri in aubergine fields. Population densities of the mirid were higher than those of the anthocorid.

Hirose (1990) explored the possibilities of using natural enemies against T. palmi in South-East Asia and Japan. The anthocorid predator Bilia sp. from Thailand was suggested to control T. palmi in Japan. The periodic release and conservation of predators was also discussed. There is increasing interest in anthocorids attacking T. palmi in Thailand, and Yasunaga and Miyamoto (1993) reported three species associated with T. palmi in aubergine gardens in Thailand; Wollastoniella rotunda is described as new and O. minutus and O. tantillus are recorded from this region for the first time. A new subgenus, Paraorius, is proposed for Orius tantillus. Two species, Wollastoniella parvicuneis and W. rotunda, were noted by Yasunaga (1995) as preying on T. palmi in northern Thailand.

There have been few attempts to use hymenopterous parasitoids for biological control of T. palmi. Hirose (1990) suggested the introduction of an unidentified eulophid larval parasitoid, Ceranisus sp., to control T. palmi in Japan. Hirose (1991) offered a convincing argument to explore further the biological control of T. palmi using Ceranisus menes, a eulophid parasitoid native to Japan and Hirose et al. (1993) reported C. menes on aubergine in home and 'truck gardens' in Japan and commented on the biology of the parasitoid and rates of parasitism.

Fungal pathogens
Saito et al. (1989) recorded the entomopathogenic fungus Neozygites parvispora for the first time on T. palmi on melon in a greenhouse in Japan. About 10% of adults and nymphs were infected, but the fungus did not control the pest population. Studies were carried out on the fungus Beauveria bassiana, isolated from T. palmi in Japan; its pathogenicity and the effect of pesticides (including fenobucarb) on hyphal growth was observed.

Hall (1992) reported a new pathogen of T. palmi in Trinidad. Approximately 80% of a population of T. palmi on an abandoned aubergine crop in Trinidad and Tobago was found to be infected by a fungus of the genus Hirsutella. This appeared to be the first deuteromycete pathogen found on T. palmi and isolated in pure culture.

The control of T. palmi by a mycoinsecticidal preparation of Verticillium lecanii was reported by Saito (1992). When a preparation of V. lecanii was applied four times weekly to melons in glasshouses in Japan, population densities of the pests were maintained at low values, compared with rapid increases observed in an untreated glasshouse.

Host-Plant Resistance

Matsui et al. (1995) screened plants from the genus Solanum for resistance to T. palmi. Four wild species, S. viarum, S. sisymbrifolium, S. nigrum and 'IK-35' (an unknown species) were identified as resistant.

Cultural Control

In the Philippines, Ruhendi and Litsinger (1979, 1982) and Litsinger and Ruhendi (1984) studied the effect of rice stubble and straw mulch on the suppression of preflowering insect pests (including T. palmi) on cowpeas (Vigna unguiculata) sown after puddled rice. They hypothesized that rice stubble and straw mulch, by covering bare soil, interfere with visual cues used by migratory thrips and leafhoppers to locate a favourable habitat.

Riddell-Swan (1988) found that mulching beds of hairy gourds with white cloth and black polythene reduced thrips populations, and surrounding the field with reflective material not only reduced the pest infestation but also improved yields. Suzuki and Miyara (1984) also studied agricultural covering materials in Japan. Nasu et al. (1986) experimented with the effect of covering aubergine with transparent plastic film in a plastic greenhouse in Japan. They found that density was low compared to the control, and the effect lasted long after the removal of the film. The invasion of thrips was effectively prevented by using cheese cloth, but the quality of fruit was low because of the raised air temperature.

Walker (1992, 1994) has reviewed the pest status of T. palmi; much of the information given here is from these reviews, together with later information. The importance of the pest on vegetable crops in South-East Asia was emphasized by a workshop held in Bangkok, Thailand (Talekar, 1991) where seven of the eight papers presented listed T. palmi as causing concern for vegetable growers in their region. However, research on this species attacking vegetables in Taiwan was reduced when it was realised that it is effectively a 'resurgence pest', that is, populations tend to increase disproportionately following heavy use of insecticides. The reasons for this phenonmenon require further study.

The economic injury density in Japan has been estimated at 0.105 adults per flower or 4.4 adults per sticky trap per day on Capsicum annuum in vinyl houses (Morishita and Azuma, 1988), assuming an acceptable yield loss of 5% of the maximum yield. Kawai (1986b) also reported that economic injury thresholds were low in vinyl houses in Japan, assuming an acceptable yield loss of 5% of the maximum yield, with 0.08 and 4.4 adults per leaf for aubergine and cucumber, respectively, and 0.11 adults per flower for C. annuum. Morishita and Azuma (1989) considered counting injured fruits to be a better sampling method than counting insects on leaves.

In the Philippines, plantings of aubergine intended for seed production had to be abandoned due to severe T. palmi damage and even the application of insecticide as often as every 4 days failed to provide satisfactory control (Bernardo, 1991). Chang (1991) lists T. palmi as one of Taiwan's most important pest thrips; damage was first observed on cucurbits in 1979, but the species was incorrectly identified as T. flavus. T. palmi has also been identified as a important pest of potato in Taiwan by SEAMEO SEARCA (1991).

However, Bournier (1986) reported that T. palmi caused insignificant damage on cotton, tobacco and wild plants in Java, Sumatra and India. Miyazaki et al. (1984) also observed, during a survey of soyabean in Java, that T. palmi did not cause heavy damage except in one instance on aubergine.

Cooper (1991b) recorded infestations of 300-700 T. palmi per leaf on aubergine and cucumber, resulting in crop losses of 50-90% in Trinidad. He suggested that T. palmi may have been brought to Trinidad in the winds of a tropical depression during 1988, but it has also been postulated that it may have gained entry through plant material from another Caribbean island, for example Martinique, where it is reported as a serious pest. Pantoja et al. (1988) noted that the climatic conditions in Puerto Rico are favourable for the early development of large populations of T. palmi on commercial crops as well as on weeds. Guyot (1988) reported the disastrous economic effect that T. palmi had in Guadeloupe when aubergine exports fell from 5000 tonnes in 1985 to 1600 tonnes in 1986, and in Martinique where 37% of the vegetable crops of the two main co-operatives were attacked by T. palmi, including 90% of aubergine crops.

In Hawaii, Johnson et al. (1989) observed that, together with Aphis gossypii, T. palmi was the major foliar pest on Oahu (1984-85). Welter et al. (1989) studied mixed infestations of T. palmi and the western flower thrips, Frankliniella occidentalis, and noted significant reductions in total cucumber yield, mean fruit size and total fruit. The population trends of T. palmi on commercial watermelon plantings in Hawaii were surveyed by Johnson (1986). Peak infestation levels varied from 2.5 to 53.6 individuals per leaf and from 18 to 97% infested vine tips per planting.

Johnson (1986) pointed out that T. palmi could establish itself in the continental USA, given the extensive flow of air traffic between Hawaii and the mainland, especially California, but it was not until 1991 that T. palmi was found in the USA, not in California as predicted by Johnson but in Florida (FAO, 1991). Heavy infestations were detected on potato, aubergine, Capsicum, Phaseolus vulgaris, yellow squash and several weeds. The likely economic impact of this pest if it became established in greenhouses in the UK was considered to be very severe, with a benefit to cost ratio for one eradication campaign being as high as 110:1 (MacLeod et al., 2004).
Related treatment support
Plantwise Factsheets for Farmers
Saman, R.; CABI, 2012, English language
Saman, R.; CABI, 2012, Dutch language
Francis, N.; CABI, 2014, English language
Han, D. N.; CABI, 2013, English language
Pest Management Decision Guides
Koech, S.; Mbevi, B.; Otipa, M. J.; CABI, 2016, English language
External factsheets
FERA Plant Pest and Disease Factsheets, Department for Environment, Food and Rural Affairs (DEFRA), English language
Plant Health Australia Factsheets, Plant Health Australia, English language
Pestnet Factsheets, Pestnet, English language
Pestnet Factsheets, Pestnet, English language
DPI NSW factsheets, New South Wales Government, Department of Primary Industries, Australia, 2011, English language
Video factsheets
Agropedia ICRISAT PPT-Videos, IIT, Kanpur, 2014, English language
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