Biological control of the diamondback moth,Plutella xylostella: A review

Abstract

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is one of the most destructive cosmopolitan insect pests of brassicaceous crops. It was the first crop insect reported to be resistant to DDT and now, in many crucifer producing regions, it has shown significant resistance to almost every synthetic insecticide applied in the field. In certain parts of the world, economical production of crucifers has become almost impossible due to insecticidal control failures. Consequently, increased efforts worldwide have been undertaken to develop integrated pest management (IPM) programs, principally based on manipulation of its natural enemies. Although over 130 parasitoid species are known to attack various life stages of DBM, most control worldwide is achieved by relatively few hymenopteran species belonging to the ichneumonid genera Diadegma and Diadromus , the braconid genera Microplitis and Cotesia , and the eulophid genus Oomyzus . DBM populations native to different regions have genetic and biological differences, and specific parasitoid strains may be associated with the specific DBM strains. Therefore, accurate identification based on genetic studies of both host and parasitoid is of crucial importance to attaining successful control of DBM through inoculative or inundative releases. Although parasitoids of DBM larvae and pupae are currently its principal regulators, bacteria-derived products (e.g., crystal toxins from Bacillus thuringiensis ) and myco-insecticides principally based on Zoophthora radicans and Beauveria bassiana are increasingly being applied or investigated for biological control. Viruses, nematodes and microsporidia also have potential as biopesticides for DBM. When an insect pest is exposed to more than one mortality factor, there is the possibility of interactions that can enhance, limit, or limit and enhance the various aspects of effectiveness of a particular control tactic. This paper reviews the effectiveness of various parasitoids and entomopathogens against DBM, interactions among them, and their possible integration into modern IPM programs.

Bottom-up effects of host plant nutritional quality on Plutella xylostella (Lepidoptera: Plutellidae) and top-down effects of herbivore attack on plant compensatory ability

“…The adaptive advantage of selecting plants of maximal quality may be to confer greater fitness on their offspring in terms of increased longevity of the adults, increased wing area and increased egg production, when food is scarce. Adults of P. xylostella are highly migratory (Chapman et al, 2002;Sarfraz et al, 2005). Therefore, the above effects are likely to be advantageous in terms of migration and re-colonization, enabling them, for example, to travel in air currents without food over several days from northern Mexico to western Canada (Dosdall et al, 2004b) and then colonize canola fields in Canada.…”

Diamondback Moth, Plutella xylostella (L.) in Southern Africa: Research Trends, Challenges and Insights on Sustainable Management Options

“…Reports from Zimbabwe indicate a failure to adhere to safety withdrawal periods, presumably due to market pressure; inefficient chemical use (only 35%-50% of sprayed chemical reach the target organism) [67,68]; application of the wrong pesticides (e.g., fungicides on insects); and abuse associated with the need to clear last seasons' expired pesticides [13,67]. This uncontrolled misuse and overuse of insecticide was reported to have significantly contributed to the increased resistance and suppression of potential biological control agents [17,18,25,30].…”

“…IPM is a huge component of climate-smart agriculture, which, since the 1990s, has been generally agreed as the only sustainable and effective method of containing or managing economic pests, including the DBM [7,17,18,25,30,74]. Since synthetic chemicals offer short-time relief, several other management strategies have been investigated on a wide range of brassica agroecosystems, but IPM remains the most viable option [18,25,82].…”

War of the wasps: is <em>Diadegma insulare</em> or <em>Microplitis plutellae</em> a more effective parasitoid of the Diamondback Moth, <em>Plutella xylostella</em>?

“…It is invasive in North America and is thought to be native to Europe or Asia (Harcourt 1954). It is a major pest of crops in the plant family Brassicaceae (which includes canola, cabbage, and broccoli), causing an estimated one billion dollars U.S. in crop damage annually (Sarfaz et al 2005a).…”