Djoko Prijono

Bio: Djoko Prijono is an academic researcher from Bogor Agricultural University. The author has contributed to research in topics: Crocidolomia pavonana & Calophyllum soulattri. The author has an hindex of 7, co-authored 42 publications receiving 199 citations.

Toxicity of Chemicals Commonly Used in Indonesian Vegetable Crops to Liriomyza huidobrensis Populations and the Indonesian Parasitoids Hemiptarsenus varicornis, Opius sp., and Gronotoma micromorpha, as well as the Australian parasitoids Hemiptarsenus varicornis and Diglyphus isaea

Abstract: Liriomyza huidobrensis (Blanchard) and Liriomyza sativae (Blanchard) are important pests of vegetable crops in Indonesia and are likely to spread to neighboring countries. Three pesticides (dimehypo, abamectin, and cyromazine) are currently used to control these pests, but there is little information on their effectiveness against field populations and on their impact on parasitoids controlling Liriomyza species. The toxicity of these chemicals to L. huidobrensis and three common parasitoids (Hemiptarsenus varicornis Gerault, Opius sp., and Gronotoma micromorpha Perkins) was therefore evaluated in Indonesia with mortality laboratory assays. All three chemicals were effective against larvae of three populations of L. huidobrensis with different histories of chemical exposure. Dimehypo caused mortality in adult Opius sp., G. micromorpha, and H. varicornis, whereas abamectin was toxic only at concentrations substantially higher than the field rate. Cyromazine did not influence survival of the parasitoids. A commonly used fungicide, mancozeb, had no impact on parasitoid mortality. Trials were repeated with a strain of H. varicornis from Australia and a different parasitoid (Diglyphus isaea) recently found in Australia. Neither parasitoid was influenced by mancozeb or cyromazine. Abamectin applied at field rates caused some mortality among the adults of both species, but was less toxic than chlorpyrifos. Abamectin produced lower LC50s against Australian H. varicornis than against Indonesian H. varicornis. These results suggest that cyromazine can be incorporated into Liriomyza control programs in Indonesia that conserve parasitoids, whereas dimehypo and abamectin need to be used cautiously. Local Australian parasitoids should help control L. huidobrensis as long as only cyromazine and nontoxic fungicides are applied.

Status Dan Mekanisme Resistensi Biokimia Crocidolomia Pavonana (F.) (Lepidoptera: Crambidae) Terhadap Insektisida Organofosfat Serta Kepekaannya Terhadap Insektisida Botani Ekstrak Biji Barringtonia Asiatica

Abstract: An examination of insect resistance was determined by several steps, i.e. standard sensitivity, resistance diagnosis, and determination of resistance level. Each phase was tested with feeding and residue contact methods at glass tube. Resistance ratio (RR) was determined by comparing LC50 value of field population with standard population. Field population of C. pavonana was classified resistant if it had RR 5 4. Biochemistry analysis of resistance was conducted to population of C. pavonana showing resistance to prophenophos insecticide. The activity analysis of acetylcholine esterase (ACHE), esterase, and Glutation Stransferase was done with spectrophotometer method. Insect which are resistant to prophenophos insecticide was tested for its sensitivity to Barringtonia asiatica seed extract. Result indicated that C. pavonana population from Pengalengan showed resistance to prophenophos synthetic insecticide. Using contact test, the highest resistance ratio value was 4.04, while by feeding assay the RR was 2.78. The study on biochemical resistance mechanisms of each field population of C. pavonana showed various activities of enzymatic detoxification. This could be due to the difference in the kind of insecticides exposed to each field population of C. pavonana. Since RR value from the contact test was higher than that of the feeding test, the resistance development of C. pavonana to synthetic insecticides was probably caused by physiological and biochemical changes in insect cuticle rather than the activity of detoxification enzyme. Methanolic seed extract of B. asiatica can be used as an alternative of resistance management of C. pavonana to prophenophos synthetic insecticide.

Synergistic action of mixed extracts of Br ucea javanica (Simaroubaceae), Piper aduncum (Piperaceae), and Tephrosia vogelii (Leguminosae) against cabbage head caterpillar, Crocidolomia pavonana

Abstract: Extracts seeds, fruits, and leaves of Brucea javanica, Piper aduncum, and Tephrosia vogelii were tested separately and also in mixture (3:2.5:1) in the laboratory for their insecticidal activity against the cabbage head caterpillar, Crocidolomia pavonana. B. javanica, P. aduncum, and T. vogelii plant materials were extracted with ethyl acetate-methanol (9:1), ethyl acetate, and ethyl acetate respectively by using maceration method. Insecticidal bioassays were done by a leaf-residue feeding method. Second-instar larvae C. pavonana were fed extracttreated broccoli leaves for 48 hrs and then were presented untreated leaves until the surviving larvae reached the fourth-instar stage. Larval mortality was assessed at 5 days after treatment, and the data analyzed by the probit method. The results showed that larval mortality started at first day treatment and increased at second day’s treatment. After changing with untreated leaves the mortality decreased significantly. Based on LC50 and LC95 values, T. vogelii leaf extract was more toxic (LC50= 0.06%, LC95= 0.12%) than P. aduncum fruit extract (LC50 = 0.24%, LC95=0.32%) and B. javanica seed extract (LC50=0.17%, LC95=0.41%). Based on value of LC50 (0.03%) and LC95 (0.05%), the toxicity of a mixture of B. javanica, P. aduncum, and T. vogelii extract (3:2.5:1) against C. pavonana larvae was very toxic. Based on the combination index according to the independent joint action model, the extract mixture had a strongly synergistic joint action against C. pavonana larvae, at level LC50 and LC95, with a combination index of 0.225 and 0.190. The mixture extract worked better than each single extract against C. pavonana

Aktivitas insektisida ekstrak buah Piper aduncum L. (Piperaceae) dan Sapindus rarak DC. (Sapindaceae) serta campurannya terhadap larva Crocidolomia pavonana (F.) (Lepidoptera: Crambidae)

Abstract: Crocidolomia pavonana is an important pest of Brassicaceous vegetable crops. Botanical insecticides are potential alternatives for the control of C. pavonana pest. Insecticidal activity of Piper aduncum and Sapindus rarak fruit extracts as well as their mixtures was evaluated against C. pavonana larvae in the laboratory. Ethyl acetate P. aduncum (EtPa) extract as well as methanolic S. rarak (MeSr) and aqueous S. rarak (AqSr) extracts were tested separately and in mixtures against second-instar larvae C. pavonana by a leaf-residue feeding method. At the LC95 level - 72 hours after treatment (HAT), EtPa extract was about 14.5 and 12.8 times, respectively, more toxic to C. pavonana larvae than MeSr and AqSr extracts. At the LC95 level, EtPa + MeSr extract mixture (1 : 10 w/w) was about 1.64 times more toxic to the test larvae than EtPa + AqSr extract mixture (1 : 10 w/w). Based on combination index at 48, 72, and 96 HAT, EtPa + MeSr extract mixture at LC50 level as well as EtPa + AqSr extract mixture at LC50 and LC95 levels had additive joint action, whereas EtPa + MeSr extract mixture at LC95 was weakly synergistic. In addition to lethal effect, the treatment with all test materials delayed the development of C. pavonana larvae from second-instar to fourth instar. Thus, EtPa, MeSr, and AqSr extracts as well as the mixtures between EtPa and S. rarak extracts are potential alternatives for the control of C. pavonana pest.

Estimating the economic cost of one of the world's major insect pests, Plutella xylostella (Lepidoptera: Plutellidae): just how long is a piece of string?

Abstract: Since 1993, the annual worldwide cost of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), control has been routinely quoted to be US$1 billion. This estimate requires updating and incorporation of yield losses to reflect current total costs of the pest to the world economy. We present an analysis that estimates what the present costs are likely to be based on a set of necessary, but reasoned, assumptions. We use an existing climate driven model for diamondback moth distribution and abundance, the Food and Agriculture Organization country Brassica crop production data and various management scenarios to bracket the cost estimates. The “length of the string” is somewhere between US$1.3 billion and US$2.3 billion based on management costs. However, if residual pest damage is included then the cost estimates will be even higher; a conservative estimate of 5% diamondback moth-induced yield loss to all crops adds another US$2.7 billion to the total costs associated with the pest. A conservative estimate of total costs associated with diamondback moth management is thus US$4 billion-US$5 billion. The lower bound represents rational decision making by pest managers based on diamondback moth abundance driven by climate only. The upper estimate is due to the more normal practice of weekly insecticide application to vegetable crops and the assumption that canola (Brassica napus L.) is treated with insecticide at least once during the crop cycle. Readers can decide for themselves what the real cost is likely to be because we provide country data for further interpretation. Our analysis suggests that greater efforts at implementation of even basic integrated pest management would reduce insecticide inputs considerably, reducing negative environmental impacts and saving many hundreds of millions of dollars annually.

Pesticidal plant extracts improve yield and reduce insect pests on legume crops without harming beneficial arthropods.

Abstract: In the fight against arthropod crop pests using plant secondary metabolites, most research has focussed on the identification of bioactive molecules. Several hundred candidate plant species and compounds are now known to have pesticidal properties against a range of arthropod pest species. Despite this growing body of research, few natural products are commercialised for pest management whilst on-farm use of existing botanically-based pesticides remains a small, but growing, component of crop protection practice. Uptake of natural pesticides is at least partly constrained by limited data on the trade-offs of their use on farm. The research presented here assessed the potential trade-offs of using pesticidal plant extracts on legume crop yields and the regulating ecosystem services of natural pests enemies. The application of six established pesticidal plants (Bidens pilosa, Lantana camara, Lippia javanica, Tephrosia vogelii, Tithonia diversifolia and Vernonia amygdalina) were compared to positive and negative controls for their impact on yields of bean (Phaseolus vulgaris), cowpea (Vigna unguiculata) and pigeon pea (Cajanus cajan) crops and the abundance of key indicator pest and predatory arthropod species. Analysis of field trials showed that pesticidal plant treatments often resulted in crop yields that were comparable to the use of a synthetic pesticide (lambda-cyhalothrin). The best-performing plant species were Tephrosia vogelii, Tithonia diversifolia and Lippia javanica. The abundance of pests was very low when using the synthetic pesticide, whilst the plant extracts generally had a higher number of pests than the synthetic but lower numbers than observed on the negative controls. Beneficial arthropod numbers were low with synthetic treated crops, whereas the pesticidal plant treatments appeared to have little effect on beneficials when compared to the negative controls. The outcomes of this research suggest that using extracts of pesticidal plants to control pests can be as effective as synthetic insecticides in terms of crop yields while tritrophic effects were reduced, conserving the non-target arthropods that provide important ecosystem services such as pollination and pest regulation. Thus managing crop pests using plant secondary metabolites can be more easily integrated in to agro-ecologically sustainable crop production systems.

Biological control of Liriomyza leafminers: progress and perspective

Abstract: There are more than 330 Liriomyza species (Diptera: Agromyzidae) and many are economically important pests of field crops, ornamentals and vegetables. Given the substantial economic losses associated with various aspects of Liriomyza feeding as well as the ability of these insects to rapidly develop resistance to insecticides, researchers from many countries have attempted to use biological control to manage these pests. Unfortunately, progress on the science and implementation of effective Liriomyza biological control is hampered by the literature being scattered widely and in many different languages. A primary goal of this review is to consolidate the available information and provide an analysis of the published work. Investigations of natural enemies of Liriomyza have identified approximately 140 species of parasitoids, a few species of predators (including nematodes), and some entomopathogens. Some species of parasitoids and nematodes have been mass-reared and used for biological control of Liriomyza species under confined environmental conditions. While chemical control is still used extensively, conservation biological control and inoculative releases are being adopted as a primary strategy for Liriomyza suppression in select situations.