This is a very difficult area.

If you go by the scientific name you are given, Planococcus sp., you should just put "mealybug". This name means various species in the genus Planococcus. There are six of these in all and they are all called mealybugs. (A further source of confusion, moreover, is that Planococcus is also the name of a genus of bacteria, which of course have nothing to do with this.)

The problem is that according to this method you will also have to put "mealybug" for "cochinilla algodonosa", which is defined in your list as Pseudococcus sp., and the members of this genus, of which there are at least twelve, are also all called mealybugs.
http://www.sel.barc.usda.gov/scalekeys/mealybugs/key/mealybu...

So you will end up using "mealybug" alone for two entries on your list, which is probably unsatisfactory.

But if you go by the Spanish common name, you may get a different answer. The fact is that there are a number of chanchitos blancos and not all of them are Planococcus. In fact the chanchito blanco "a secas" is not a Planococcus; it is Pseudococcus calceolariae:
http://biblioteca.duoc.cl/bdigital/insectario_digital/plagas...

Indeed here, in a scientific document from Chile on treatment of chanchitos blancos, they are identified as primarily Pseudococcus sp., and "chanchito blanco" is said to be a synonym of "cochinillo harinoso".
http://www.inia.cl/medios/biblioteca/boletines/NR37205.pdf

In English Pseudococcus calceolariae is called the citrophilus mealybug
http://www.sel.barc.usda.gov/scalekeys/mealybugs/key/mealybu...

But this is not the one they mean; apart from being a different genus, it does not attack grapes or vines, as you can see from the biblioteca.duoc source cited above.

So I think this must be referring to insects that are called chanchito blanco in Spanish, that belong to the genus Planococcus and that attack grapes.

There is two that fit the bill:

Pseudococcus viburni, called "chanchito blanco de la vid" of "chanchito blanco de los frutales" in Spanish and "obscure mealybug" in English
http://biblioteca.duoc.cl/bdigital/insectario_digital/plagas...
http://www.bayercropscience.cl/soluciones/fichaproblema.asp?...
http://www.sel.barc.usda.gov/scalekeys/mealybugs/key/mealybu...
http://en.wikipedia.org/wiki/Pseudococcus_viburni

2. Planococcus ficus, sometimes called "chanchito blanco" in Spanish, though also known as "cochinilla harinosa de la vid", and "vine mealybug" in English.
http://www.pv.fagro.edu.uy/cursos/pvf/Materiales/Enf_Vid-PVF... (p. 5 top)
http://www.sinavimo.gov.ar/plaga/planococcus-ficus
http://www.sel.barc.usda.gov/scalekeys/mealybugs/key/mealybu...

So I think it must be one of these, and I would suggest you put both as alternatives.

The other mealybug that attacks grapes and vines is the grape mealybug, Pseudococcus maritimus, but it is the wrong genus: it is not a Planococcus. In Spanish it is also sometimes called "chanchito blanco de la vid":
http://www.sag.gob.cl/common/asp/pagAtachadorVisualizador.as...
(see sheet 1 cell P40).

There are other chanchitos blancos that are Planococcus but don't attack grapes or vines, notably the citrus mealybug, Planococcus citri, which is "chanchito blanco de los cítricos" in Spanish:
http://biblioteca.duoc.cl/bdigital/insectario_digital/plagas...
http://www.sel.barc.usda.gov/scalekeys/mealybugs/key/mealybu...

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Note added at 8 hrs (2012-07-29 11:17:37 GMT)
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The fact is that your document makes a false distinction by saying that "cochinillas algodonosas" belong to the genus Pseudococcus and "chanchitos blancos" belong to the genus Planococcus. This is at best an oversimplification. Anyway, in English all of them are mealybugs. What I've tried to do here is give an answer that is scientifically accurate and fits your text but allows you to use different English common names for the two entries (though inevitably both will include the word "mealybug").

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Note added at 8 hrs (2012-07-29 11:20:40 GMT)
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After all that, I've spotted a typo in the answer line: it should be obsCure, not "obsure".

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Note added at 14 hrs (2012-07-29 17:32:05 GMT)
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And another slip above, this one really embarrassing: the obscure mealybug is not Pseudococcus viburni but Planococcus viburni. If it were the former, it would destroy my argument. Very sorry about this! It's terribly confusing, and you have to keep four factors in mind: scientific name, Spanish common name, English common name, and habits.