He told local media outside the House that obstacles raised against the use of genetic modification technology hold back efforts of peasants, which means millions of lives of Tanzanian people are thrown back owing to an archaic rule of using only natural varieties.
They are prone to diseases and host destructive pests, for their excess sugar that attracts the pests in the food cycle.
Only recently the country was counting losses arising from invasion of fall armyworms, a variety of worms that multiplies and moves in massed numbers like quelea quelea in the sky, though their closest cousins are moths rather than birds.
Still their operating principle is the same, as in like manner as bees moving from one flower to another, what they seek is nectar, a sugar which they need to make food that is often taken away by humans as a harvested product, honey.
When genetically modified organisms are used, the sugar is replaced by a salt compound which can feed the stem with nutrients, but is wholly unattractive to pests.
What was surprising about the Mwanga MP's intervention, speaking more like a veteran academic from the Sokoine University of Agriculture (SUA) than a veteran cabinet minister, was that for some reason he did not succeed to express these sentiments when he was still in the government.
Since there is something that is known as collective responsibility that applies to all cabinet ministers, it follows that even if he was the sector minister at some point (as he held various portfolios in his 12 years as cabinet minister, from late 2005 to late 2017) he could not have taken the radical measure all alone. It couldn't be a turn of mind just recently.
If one assumes that this is the case, there is a definite omission in his parliamentary intervention, namely by sending or directing his criticism to the government, that by raising obstacles to applied technology in the agro sector.
This was impeding progress in agriculture and deliberately impoverishing people. If himself as minister he wasn't able to take the measure, including a rather brief stint as minister for Agriculture, Food and Cooperatives for 14 months, late 2010 to early 2012.
It means that those in government often find that their hands are tied. It isn't again relevant to say it's the position of the president, as he is definitely advised.
In that sense the former minister's intervention was helpful but only in part, as he took a routine viewpoint as a parliamentarian to castigate the government, knowing fully well he has nothing to lose having quit the cabinet position, or asked to leave.
In addition, he may have opted to frame the matter in a critical tone so that he is understood as doing parliamentary work and as consultant to academic concerns on the GMO ban which at times it appears will be removed, only for controls to be reiterated.
Still there was something that he could have taken up, explaining why the government feels its hands are tied on this issue, even paralysed.
As 'nature abhors a vacuum,' one can't say that the former minister just forgot or did not think of this issue, but rationally he opted not to do so, partly as a matter of solidarity with those in government, that if any such explanation is needed, they they will provide it.
In that sense the proper role for a parliamentarian in that regard is to criticise the government to insisting on hurdles on application of genetic modification, which means he remains an MP and has forgotten all cabinet rationality put at work in withholding permits for such activities or importation of such products, technology. And he isn't going to divulge those secrets.
Thus activists for GMO adoption had a sigh of relief that a former cabinet minister had derided that habit, but did not obtain insights as to what holds back the government from rendering those permits.
At the same time, to his credit, Prof. Maghembe pointed at paradoxes in refusal of GMO seeds for instance in cotton, but then 75 per cent of clothing imported from outside is made with the GM products that we refuse, which this implies we are denying ourselves market opportunities.
The former SUA don didn't address the biodiversity concerns perennially raised by environmentalists, implying that this ignores a higher value, human welfare.
Perhaps the don could in future go a little further, in the direction of a contributor to this newspaper of late, urging the formation of a liberal convention in African countries, but sounding worried that this will in a number of areas disturb solid conventions, habits.
Genetic modification for instance is hindered not just by NGO concerns about biodiversity, since governments don't always pay attention to those sirens, as in that context there wouldn't be many oil and gas fields still continuing, now.
What helps NGOs in battling a shift to genetic modification is zealous nationalism, that we give multinationals our market, to sell their seeds, etc.
The former minister has not delved into the rationale of the ban on GMO application but has raised a red light on the supposed benefits to the people when we use 'our' seeds instead of 'their' seeds.
His voice has helped boost that of pro-GMO activists but they are hopelessly outnumbered, though a silver lining is seen on the horizon, as Rwanda, Uganda and others are seeking to set up localized centres for testing of GMO products and verification, an operation not quite far from what is habitually done by the Tanzania Bureau of Standards or the Tanzania Food and Drugs Authority.Few such measures are being undertaken here as yet.
In that case it is difficult to estimate the proper value of the former minister's contribution to changing the tone of the dialogue in the country on genetic modification, as he did not address the key issue of why the government feels tied about the issue.
But even if in a secondary way, he has broadened the question of material interest from its superficial view at a bureaucratic and NGO level as tied to a principle of ours and theirs, to a substantive concern as to which form of technology benefits the peasants.
In removing the view of local seeds from their natural pedestal as God-given and having the same respect level as 'their' seeds, or being better as they are natural, to seeing them as pre-technological and wasteful, the don must be saluted.