Caribbean fruit fly, also known as Caribfly or Anastrepha suspensa , is a major tephritid pest of guavas. A virulent entomopathogenic nematode (EPN) species was investigated to suppress the fruit-to-soil stages of Caribflies, which are also attacked by the koinobiont parasitoid Diachasmimorpha longicaudata in south Florida. The main objective was to develop a feasible and cost-effective EPN-application method for integrated pest management (IPM) of Caribfly to improve guava production. Naturally infested guavas were treated with increasing Heterorhabditis bacteriophora infective juvenile (IJ) concentration or rate (0, 25, 50, …, 1,600 IJs cm -2 ) in field trials to measure the optimum IJ rate and then examine sensitivity of producing guavas to inclusion of Heterorhabditis bacteriophora in Caribfly IPM plans. Relative survival of Caribfly in treatments significantly decreased with increasing IJ rate from 0 to 100 IJs cm -2 . Similarly, probability of observing large numbers of parasitoid wasps ( Diachasmimorpha longicaudata ) in EPN treatments significantly declined with increasing IJ rate (0-100 IJs cm -2 ), even though the non-target effects of Heterorhabditis bacteriophora on relative survival of Diachasmimorpha longicaudata could not be determined because of few emerging parasitoid wasps. Optimum suppression (⩾ 60%) of Caribfly was consistently achieved at 100 IJs cm -2 or 17,500 IJs fruit -1 . Profitability analysis showed that Heterorhabditis bacteriophora can be included in Caribfly IPM tactics to produce guavas. Costs of EPNs in Caribfly IPM are minimized if Heterorhabditis bacteriophora is strategically applied by spot treatment of fruit. Repayment of costs of EPN-augmentation by spot treatments appears achievable by recovering 5.71% of the annual yield losses (⩾1,963 kg ha -1 ≈ US$ 8,650 ha -1 ), which are largely due to Caribfly infestation. Hectare-wide EPN-augmentation (or broadcasting) method requires more fruit recovery than the total annual yield losses to repay its high costs. Profitability of guava production in south Florida will not be very sensitive to marginal costs of the spot treatment method, when compared to the field-wide broadcasting of Heterorhabditis bacteriophora .

https://exeley.mpstechnologies.com/journal_of_nematology/pdf/10.21307/jofnem-2018-039

Responses of Anastrepha suspensa, Diachasmimorpha longicaudata, and Sensitivity of Guava Production to Heterorhabditis bacteriophora in Fruit Fly Integrated Pest Management.

/pdf/genetic-resistance-of-wheat-towards-plant-parasitic-1iyyh51mru.pdf

Genetic Resistance of Wheat towards Plant-Parasitic Nematodes: Current Status and Future Prospects

Global trading of plant materials, in combination with agricultural practices, may facilitate the spreading of cyst nematodes to so far non-infected areas. Recently Potato Cyst Nematode (PCN) was recognized to be present in Indonesia and both diversity and distribution require further study. Assessment of PCN populations was done by collecting soil samples, determination of morphological characteristics in combination with ITS rDNA and COI mtDNA sequencing. Thirty-seven soil samples were collected from potato fields in the Indonesia archipelago. The results showed the presence of Globodera rostochiensis in 22 out of 37 sampling fields, namely North Sumatra (6 fields), Central Java (12 fields), East Java (3 fields), and -for the first time- in Sulawesi (North Sulawesi) (1 field). The highest observed density was found in Banjarnegara (Central Java), i.e., 872 cysts 100 ml soil−1. Globodera pallida was not recovered. Both ITS and COI characterisation of Indonesian PCN (G. rostochiensis) revealed the virtual absence of sequence variation as compared to most PCN from the rest of the world; the COI sequences were identical to the most common and mostly distributed haplotype around the world. Microsatellite genotyping indicated a higher genetic diversity for populations from East Java than for populations from North Sumatra, suggesting that cysts at the origin of populations in North Sumatra were coming from populations in East Java. These data on species identification, population density, genetic diversity, and distribution of potato cyst nematode over the Indonesian archipelago constitute the very basis for the design of environmentally-sound and effective PCN control strategies.

Distribution, DNA barcoding and genetic diversity of potato cyst nematodes in Indonesia

Six months field experiment were set up from June to November in Department of Botany, University of Karachi to investigate the influence of mangroves (Avicennia marina, Rhizophora mucronata) parts separately or combined parts for the control of Meloidogyne javanica (Treub.) Chitwood. Mangroves parts including leaves, stem, pneumatophore and combined parts were applied to field in form of powder at rate of 60 g/plot, capsules and pellets at 120 g/plot. Results pertaining to seed germination percentage, plant length, plant weight and yield showed outstanding improvement in both okra and mung bean when combined parts pellets of A. marina and R. mucronata were used. All parts of A. marina, R. mucronata pellets and powder were effective in controlling of M. javanica infection but maximum reduction in root knot nematode were obtained by the amendment of mangrove combined parts powder.

Mangrove formulations for the management of meloidogyne javanica (treub) chitwood under field conditions

MANEVA, S. and Zl. TRIFONOVA, 2015. Globodera rostochiensis population density effect on potato growth and yield. Regression models estimation. Bulg. J. Agric. Sci., 21: 815–821 Effect of initial population densities (Pi) of Bulgarian population of Globodera rostochiensis on the population dynamics and potato plants growth and yield was investigated in glasshouse and estimated using mathematical models. Potato cv. Nadejda seedlings were inoculated with Pi levels of 0, 0.1, 0.2, 0.5, 1, 2, 4, 8, 16, 32, 64 or 128 second stage juveniles/cm 3 soil. The relation between Pi and final population density (Pf) was linear and DWLS regression described the relation of nematode reproductive index (Ri) and Pi. The linear regression with lg(X+I) transformation has been used to model the Pi and Pf effect on both, potato height and yield. Tolerance limit of potato to G. rostochiensis was between 0.5 and 1 juveniles/cm 3 soil. The reduction of yield was significant different at 1.0 Pi. The model predicted that 4.0 Pi caused 50% yield loss and the maximal yield suppression of 87.6% occurred at 128 Pi. Maximum Ri of 27.0 occurred at 4.0 Pi, suggesting an interspecies competition.

/pdf/globodera-rostochiensis-population-density-effect-on-potato-prwyjwjw5p.pdf

Globodera rostochiensis population density effect on potato growth and yield. regression models estimation

The golden potato cyst nematode, Globodera rostochiensis is globally recognized one of the most serious biotic constraints of potato crop. The nematode juveniles infest the roots of plant, which leads to yield loss. The pathogenic potential and reproduction fitness of G. rostochiensis on two potato cultivars Marfona and Spunta were determined in two pot experiments with and without the nematicide Aldicarb (G 10%) application. In both experiments, increasing initial population densities (Pi) of the nematode in soil was associated with reducing in growth and yield of the plants. These inverse relationships were highly significant and clearly demonstrated using nonlinear regression analysis. The increasing rate of the Pi reduced the multiplication rate of G. rostochiensis in the plants. In treatments, where nematicide was not applied, increase in the Pi levels resulted in yields decreasing exponentially to a maximum tuber yield loss of >50% at 32 to 64 eggs per g soil in cvs. Spunta and Marfona. The nematicide application improved the tuber yield as much as 25% and 30% in cvs. Spunta and Marfona, respectively. © 2013 Friends Science Publishers

M. Hajihasani

Papers

Estimation of yield damage in potato caused by Iranian population of Globodera rostochiensis with and without aldicarb under greenhouse conditions.